package_daemon: Do not delete roots on destruction.

Instead just release our reference to them and clear the list.
Should fix #17580.

Package kit: more style fixes.

Pointed out by Axel this time. Thanks!

chroot support in package kit: style fixes

- Catching an exception in the normal flow is not a good thing, instead,
test before calling the function (I've been doing too much python
lately)
- Avoid using uninitialized nodeRef if there is no system root and also
no specified root in the message.

Thanks to Ingo or the code review.

Fix use of findpaths from inside chroot

The package kit needs to provide the package daemon with the node_ref of
the root directory, so the package daemon gives the correct results when
the request comes from inside a chroot.

Moreover, the package kit must be able to handle a root with a system
but no home package dir, as is the case inside the chroot environment
created by haikuporter.

Fixes #12602.

package daemon: Let Root know whether it is the system root

package daemon: Add support for activation change request

* daemon: Handle new request B_MESSAGE_COMMIT_TRANSACTION. It activates
and deactivates given sets of packages. The new packages must be
placed in a directory in the administrative directory. The daemon
moves them to the packages directory and the deactivated packages to
a subdirectory it creates. It also save the old activation state
there.
* Add private BActivationTransaction, describing an activation change
transaction.
* BDaemonClient: Add CommitTransaction(), which sends a given
BActivationTransaction as a B_MESSAGE_COMMIT_TRANSACTION request to
the daemon.

Completely untested yet.

Implement getting a BInstallationLocationInfo

* Rename PackageDaemonDefs.h to DaemonDefs.h.
* Replace the MESSAGE_GET_PACKAGES by the new
B_MESSAGE_GET_INSTALLATION_LOCATION_INFO, which not only returns the
packages, but also other information about the installation location.
* daemon: Volume: Implement a change count which is bumped whenever
packages are activated/deactivated/added/removed. Cache the reply
for a location info request, using the change count to check whether
it is still up-to-date.
* Add private BDaemonClient for communication with the daemon.
* BRoster:
- Add GetInstallationLocationInfo() using BDaemonClient.
- Reimplement GetActivePackages(), using
GetInstallationLocationInfo().

package kit: get active packages list from daemon

* daemon: Implement private message protocol to retrieve the active
packages.
* BPackageRoster::GetActivePackages(): Get the active packages list
from the daemon.

package daemon: Make all work with the packages asynchronous

There's now a worker thread per Root that does all the work that can
take time. Node monitoring notifications received in the main thread are
just pushed into the worker's job queue, so the application looper
remains responsive.

package daemon: Add package monitoring and de-/activation

* packagefs: Disable (comment out) node monitoring of the packages
directory.
* package daemon:
- When a packagefs volume is added load the respective packages
directory and get from the volume which of the packages are
activated.
- Add node monitoring for the packages directory and
activate/deactivate packages as packages are added/removed.

Add the humble beginnings of the package daemon

It doesn't really do anything yet save for tracking what packagefs
volumes are mounted and unmounted.

package daemon: Let Root know whether it is the system root

package daemon: Add support for activation change request

* daemon: Handle new request B_MESSAGE_COMMIT_TRANSACTION. It activates
and deactivates given sets of packages. The new packages must be
placed in a directory in the administrative directory. The daemon
moves them to the packages directory and the deactivated packages to
a subdirectory it creates. It also save the old activation state
there.
* Add private BActivationTransaction, describing an activation change
transaction.
* BDaemonClient: Add CommitTransaction(), which sends a given
BActivationTransaction as a B_MESSAGE_COMMIT_TRANSACTION request to
the daemon.

Completely untested yet.

Implement getting a BInstallationLocationInfo

* Rename PackageDaemonDefs.h to DaemonDefs.h.
* Replace the MESSAGE_GET_PACKAGES by the new
B_MESSAGE_GET_INSTALLATION_LOCATION_INFO, which not only returns the
packages, but also other information about the installation location.
* daemon: Volume: Implement a change count which is bumped whenever
packages are activated/deactivated/added/removed. Cache the reply
for a location info request, using the change count to check whether
it is still up-to-date.
* Add private BDaemonClient for communication with the daemon.
* BRoster:
- Add GetInstallationLocationInfo() using BDaemonClient.
- Reimplement GetActivePackages(), using
GetInstallationLocationInfo().

package kit: get active packages list from daemon

* daemon: Implement private message protocol to retrieve the active
packages.
* BPackageRoster::GetActivePackages(): Get the active packages list
from the daemon.

package daemon: Make all work with the packages asynchronous

There's now a worker thread per Root that does all the work that can
take time. Node monitoring notifications received in the main thread are
just pushed into the worker's job queue, so the application looper
remains responsive.

package daemon: Add package monitoring and de-/activation

* packagefs: Disable (comment out) node monitoring of the packages
directory.
* package daemon:
- When a packagefs volume is added load the respective packages
directory and get from the volume which of the packages are
activated.
- Add node monitoring for the packages directory and
activate/deactivate packages as packages are added/removed.

Add the humble beginnings of the package daemon

It doesn't really do anything yet save for tracking what packagefs
volumes are mounted and unmounted.