Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r259266:

Fix multi-repository support by properly respecting 'enabled' flag.

This will read the REPOS_DIR env/config setting (default is /etc/pkg
and /usr/local/etc/pkg/repos) and use the last enabled repository.

This can be changed in the environment using a comma-separated list,
or in /usr/local/etc/pkg.conf with JSON array syntax of:
REPOS_DIR: ["/etc/pkg", "/usr/local/etc/pkg/repos"]

Approved by: bapt (mentor)

MFC r258348:

Document 'enabled' as boolean instead of string.

Approved by: bapt (implicit)
Approved by: re (gjb)

MFC r257668:

Use proper capitalization for FreeBSD.org

Approved by: bapt
Approved by: re (gjb)

MFC r257505:

Add -f support to 'pkg bootstrap' and 'pkg add' to force installation
of pkg(8) even if already installed.

This is useful if you somehow messup pkg(8) and need to reinstall from
remote with it already being registered in the pkg(8) /var/db/pkg database.

Also add some sanity checks to 'pkg add'.

Approved by: bapt
Approved by: re (glebius)

MFC r257378,r257400,r257402,r257440:

Add a pkg(7) manpage for bootstrap

Approved by: bapt
Approved by: re (gjb)

Add a pkg(7) manpage for bootstrap

Approved by: bapt
MFC after: 2 days