[SRU bionic/linux] build and sign wireguard.ko in the primary package

[Andy Whitcroft]

We are slowly enabling signed wireguard modules in existing LTS series.
These patch kits bring signed the wireguard.ko module bionic/linux.  The
userspace support packages are now in -proposed for this in bionic.
These should be tested and promoted this week.

This consists of two updates one for bionic:linux and the other for
bionic:linux-meta.  The first three patches apply to bionic:linux, the
remainder to bionic:linux-meta.

Once applied ./update-dkms will need to be run in bionic:linux to pick
up the official version.  Also expect the ./update-version in
bionic:linux-meta to pick up the dkms-versions file.  We also need to
start enabling this in all derivates which we can do as part of spinning
the next cycle.

Proposing for SRU to bionic:linux.

-apw