The apt-key command takes an optional --keyring parameter representing
the path to a specific GPG keyring to operate on. If it's not given,
the command operates on all keyring files, i.e., /etc/apt/trusted.gpg
and /etc/apt/trusted.gpg.d/*.gpg.
This change adds a 'keyring' parameter to the apt_key module and
propagates it down to the apt-key command line. The main use case this
supports is organizing keys for third-party repos into individual
keyrings in /etc/apt/trusted.gpg.d, rather than putting them all in
the default keyring.
Migrated all examples: in DOCUMENTATION=''' string to standalone EXAMPLES=''' string
Added deprecation warning to moduledev.rst and remove deprecated example from it
Fixed up a few typos and uppercased some acronyms.
add consistency to how EXAMPLES are formatted
