Create SDDS build rules for merging SDC metadata files with UI Kit code

Assigning to Richard to figure out approach.

Add parent.

This is not a priority for Barcelona so postponing.

This one would be a good one for Joshua or Richard.

But note that we may ditch using the components module which means we'd need to update all the namespaces as part of the build:

#3469985: Reconcile components module vs SDC namespaces for SDDS includes/embeds

Given we have so much going on with critical bugs, this would be a distraction, so moving back to postponed.

Removing parent. This can be considered post-Barcelona.

Reopening this as we should try to do this one soon.

Jacob will take a stab at this after he's worked on some other things.

Unassigning because alan.cole has improved the build rules in CT and that will get merged into that repo soon so we should get that in here first.

Postponed on #3481579: Port improved CivicTheme build code to SDDS