(D-Day) Governance systems (AH, Collectives) can trigger the force_set_current_code functionality for rescue purposes

[bkontur]

Relates to: #5588 (comment)

Context

As part of the D-Day governance solution, after AHM, we want to ensure the ability to rescue stalled parachains.

Currently, parachain rescue is performed using the Paras::force_set_current_code(para_id, new_code) call directly on the relay chain. However, with AHM, governance will be moved to AssetHub, making force_set_current_code quite expensive. As an alternative, a pre-authorized code hash feature has been proposed: #7574.

Also we need this: #78

Solution

• 1. Setup Collectives track or whatever to issue pre-authorized code hash on the relaychain
• 2. Ensure AssetHub governance can issue pre-authorized code hash on the relaychain

TODO

• add (emulated) tests for Collectives->Relaychain and AssetHub->Relaychain
• create fellows tracking issue
• Fetch parachain runtime code from the relay chain #78