Address FAST project re-alignment

[jattasNI]

🧹 Tech Debt

Various FAST packages that we depend on are going away or changing their mission:
microsoft/fast#6955

We need to come up with a migration plan so that we don't get stuck in a situation where there is a bug / feature gap in our dependency that can't be fixed.

This is the high level issue to trigger brainstorming; we'll probably break it into separate issues / HLDs.

Decision points include:

1. fast-foundation component base classes are going away
2. fast-foundation utilities are going away
3. fast-element legacy branch is receiving very little attention in favor of their vNext branch

[jattasNI]

First step is for @rajsite to schedule a team brainstorming session to sketch out a rough plan.