BMenu: use std::stable_sort to implement SortItems

This fixes two problems:

- Use of a stable sorting algorithm makes sure that the relative
position between items that compare equal are not modified
- More importantly, the compare function in BList passes a
pointer-to-pointer (in this case a BMenuItem**) and this was masked by
the casts due to BList lack of type safety. So, BMenu::SortItems was
not working at all when trying to use it as its prototype would imply.

NetworkStatus and Network preferences worked around this by doing the
extra dereferencing in their compare functions. I did not find any
other places in Haiku where this function is used (it was introduced
specifically for this in hrev55562). All 3rd party code that had a
similar workaround will have to be fixed to remove it (if there is
anything using that function).

Change-Id: Ia78fd1363f2c012f6eff6f9a47e8b3aac2752ebd
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7356
Reviewed-by: Niels Sascha Reedijk <niels.reedijk@gmail.com>

Network: Sort network menu items w/o deleting

* Delete dropped out networks.
* Add in newly discovered networks.
* Add static (aka class) compare method to WirelessNetworkMenuItem
that is used to sort items by signal strength descending.

Add == operator to wireless_network struct to determine if
existing items have a known network attached.

Remove the non-network items from the menu, save them, sort
network menu items, then add non-network items back into the
menu.

Update NetworkStatus preflet to use same compare method as Network
preflet. signal_strength_compare function had a bool return value
instead of int which worked to sort items the first time, but does
not work on successive compares.

By not deleting and recreating the menu items each Pulse(),
the Network preflet no longer crashes on update. The menu flashes
on update still but doesn't crash.

Fixes #12024

Change-Id: Ie5b22cea4e66350b9c5df8e3b8de266ede50ad6d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4243
Reviewed-by: John Scipione <jscipione@gmail.com>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Reviewed-by: Axel Dörfler <axeld@pinc-software.de>

Whitespace cleanup: two blank lines between functions.

NetworkStatus: show authentication mode in WiFi list. #9666

* now WirelessNetworkMenuItem appends authentication mode to its label

Signed-off-by: Matt Madia <mattmadia@gmail.com>

* Moved WirelessNetworkMenuItem into its own file.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39833 a95241bf-73f2-0310-859d-f6bbb57e9c96

Whitespace cleanup: two blank lines between functions.

NetworkStatus: show authentication mode in WiFi list. #9666

* now WirelessNetworkMenuItem appends authentication mode to its label

Signed-off-by: Matt Madia <mattmadia@gmail.com>

* Moved WirelessNetworkMenuItem into its own file.
* Minor cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39833 a95241bf-73f2-0310-859d-f6bbb57e9c96