Backport of Core PR #10849: Multiwallet: simplest endpoint support
6b9faf7 [QA] add basic multiwallet test (Jonas Schnelli)
979d0b8 [tests] [wallet] Add wallet endpoint support to authproxy (John Newbery)
76603b1 Select wallet based on the given endpoint (Jonas Schnelli)
32c9710 Fix test_bitcoin circular dependency issue (Jonas Schnelli)
31e0720 Add wallet endpoint support to bitcoin-cli (-usewallet) (Jonas Schnelli)
dd2185c Register wallet endpoint (Jonas Schnelli)
Depends on D985, and D1003
Closes T186