Meta-package naming for Xenial LTS backports

[Andy Whitcroft]

We have been discussing some naming for new meta-packages to allow for
automatic rolling upgrades between Hardware Enablement (HWE) kernels
within the LTS series.  This thread aims to firm those up.

Currently we have meta-packages of the following forms:

    linux{,-image,-headers,-signed,-tools}-<flavour>[-<variant>]

The flavour then represents the primary use case for the kernel (for
example generic and lowlatency) and the optional variant currently is
used to identify the HWE kernels (lts-<series>).  For example:

    linux-image-generic-lts-xenial

The desire is to offer a rolling HWE kernel, this means a kernel variant
which is updated automatically to the latest available HWE kernel within
the LTS.  We would expect that to update to the next HWE kernel at each
point release.  We wish to offer this in two forms, rolling until we
reach the next LTS release and continuing to roll after an upgrade.
Finally we wish to be able to offer early accesss to these updates as
soon as they are available for testing purposes.

We are proposing the following variants:

    -hwe-16.04
    -hwe-rolling
    -hwe-16.04-early
    -hwe-rolling-early

So for example:

    linux-generic-hwe-16.04

/me puts up some substantial scaffolding round his bikeshed.

-apw