Remove bridges subtree (#5752)

* remove bridges folder

* remove BRIDGES.md

* remove bridges mentions from top Cargo.toml

* remove bridges from CODEOWNERS

* remove bridges mentions from testing.md

* remove bridge pallets from Rococo/Wococo runtime

* also remove from node

polkadot/Cargo.toml

@@ -114,10 +114,6 @@ members = [
 	"utils/generate-bags",
 ]
 
-# We want to be able to build the bridge relayer without pulling it (and all of its
-# dependencies into the Polkadot workspace)
-exclude = ["bridges/relays/bin-substrate", "bridges/bin/rialto/runtime", "bridges/bin/millau/runtime"]
-
 [badges]
 maintenance = { status = "actively-developed" }