CIP: Add RT enabled builds and tests

[patersonc]

This PR does the following:

1. Commit 1: Adds a build for each CIP kernel/arch that enables the preempt_rt configuration fragment
2. Commit 2: Switches our default testing to only use the CIP reference platforms
3. Commit 3: Creates a cyclicdeadline test for each build from 1.
4. Commit 4: Creates a cyclictest test for each build from 1.

All done with heavy (hopefully correct) usage of anchors.

I've marked it as draft as I'd very much like for this PR to be tested before it's merged, as I expect to find lots of issues!
If anyone can guide me on how I can do this I'd appreciate it.

Thanks!