Build a common kernel for the servers and Qubes workstation.

[zenmonkeykstop]

For Qubes v4.0, the u2mfn module was required - this meant that a separate grsec kernel build for SecureDrop Workstation was also required. Said module is no longer needed AFAICT for 4.1, so we should look into building a single kernel that will work for both the servers and workstation.

Potential upsides: reduced maintenance, simultaneous updates across the system.

Potential downsides/blockers: there may be device support etc that we need for servers but would prefer not to include for the workstation appVMs.

[eaon]

I'm wondering if we could ship a package with appropriate modules for server device support, which we would not include in the workstation template?