Document TSC -> Alloy migration

[BobWall23]

Once most of the issues in this epic are done, update the documentation to include all the new functionality consumers may need to migrate.

[giarc3]

We decided to move this out of the 1.0 epic as we're not reaching full feature parity with prior TSCs until 1.1 (batch functions)

[skeet70]

Moving it back into 1.0 because it's not a 1.0 if people don't know how to migrate to it. If 1.1 has batch, put a disclaimer at the top of the migration guide that they can't migrate until 1.1 if they're using batch. The rest of the guide can be written.