[Bridges SDK] Deploy a new test bridge to replace Rococo <> Westend

[acatangiu]

Rococo Relay chain and all its parachains were shut down mid October. This has left us without a test bridge where we can validate new bridge features/configurations and new offchain relayer functionality.

In the short-term we will keep around the Rococo code so that we can still "deploy" local Rococo<>Westend zombienet testnets and test things on local setups.
However, we can't keep maintaining the Rococo runtimes for long just for local bridge tests, the maintenance and development costs like integrating new features (even if bridge-unrelated) in this network are too high.

So in the long-term we have two options, both of which require significant amount of work:

1. Paseo<>Westend bridge: Take ownership of Paseo Bridge Hub and Paseo Asset Hub runtimes and decouple their PolkadotSDK deps from the other Paseo runtimes so that we can iterate fast and use latest SDK releases to test things (while the rest of Paseo uses the older SDK deps used by Polkadot and Kusama runtimes).
2. Use Polkadot Doppelganger #4230 when it will be available to locally fork Westend and regenesis another Westend and basically have an on-demand Westend1 <> Westend2 test bridge.

[kianenigma]

Another concern would be that our templates and tutorials all start on the basis of Rococo. The fewer runtimes we have, the better. I hope we can move all of this to either Paseo or Westend as well.