Restore Rococo <> Wococo bridges (headers + messages)

[svyatonik]

May be tested with scripts in https://github.com/svyatonik/rococo-wococo.test and updated relayer from paritytech/parity-bridges-common#1241 . This version:

1. doesn't include any message filters;
2. needs message relayers to be running in altruistic mode, because R/W tokens has no value;
3. requires relayers fund account creation on R/W once this goes live;
4. since we have been running R<>W headers bridge for a while and I believe Rococo hasn't been restarted since that, we don't need to (re)initialize headers bridge. Instead we shall run standalone headers relay for a while && let it sync missing headers.

[tomusdrw]

since we have been running R<>W headers bridge for a while and I believe Rococo hasn't been restarted since that, we don't need to (re)initialize headers bridge. Instead we shall run standalone headers relay for a while && let it sync missing headers.

Actually it was restarted and the header relayers are not running since then. We need to initialize it from scratch and I think it's best to run the complex relayer right from scratch.

[svyatonik]

bot merge