CI jobs lack coverage for a large fraction of slaves (CDC slaves in particular)

[alessandrothea]

The CI build jobs used to validate pull requests and releases don't provide any coverage for a large fraction of the slaves distributed with ipbus, which are extensively used in ipbus-based projects. Also, the ipbus-example include only slaves running on ipbus clock, ignoring potential clock constraint issues in example board designs.

This was recently exposed in a project built against ku105 and zcu102 boards. The same payload code would build on the former and fail on the latter because of the different apporach to timing constraints (see #107). Such a discrepancy and the ensuing error must be covered by CI tests.