Extract some general utility crates for building parachains

[rphmeier]

We have built a few generalizable capabilities within Blobs which may be useful to the broader ecosystem of Substrate users. I'd like to find ways to split these from the main codebase and publish on crates.io . A few examples that come to mind:

1. The XCM configuration for a chain to use only the relay chain's native asset
2. The collator implementation which does not build blocks when there are no transactions, incoming messages, or runtime upgrades
3. Fee adjustment which accounts for skipped blocks.