Migrate asset transfer over bridge to polkadot-fellows

[bkontur]

At some point (coming soon), the system parachain production runtimes will be removed from polkadot-sdk, so then we will need to split PR:

• cumulus pallets and stuff to polkadot-sdk (already as a part of PR)
• prepare PR for relevant runtimes changes to polkadot-fellows for AssetHubKusama/Polkadot and
  • include Set up constants in P<>K bridge to avoid going through governance again #2639
• write RFC to polkadot-felllow
  • every big update of this runtimes should have approved RFC, which should pass goverance on-chain voting on Polkadot
  • here is repo with RFCs: https://github.com/polkadot-fellows/RFCs/

[bkontur]

closing, this was done by polkadot-fellows/runtimes#108