UBUNTU: [Packaging] support standard testing access to flavours
In order to allow testing to select appropriate meta packages to install
specific flavours out of a specific source package without having to
understand the currently active variants we are adding additional names
for the existing meta packages. These come in the form of Provides:
which are static relative to this source and flavour combinations,
additionally they encode a preferred flavour for ADT testing which is
clueless about flavours:
The primary interface is --full-- which installs the linux-generic
style top-level meta package which then installs the linux-image-* and
linux-headers-* variants. Should we later need those separatly we can
add --image-- and --headers-- interfaces; currently ADT installs both,
and RT testing installs the top level meta. There are also equivalent
--modules-extra-- provides so they can be added if testing requires it.
