Merge bitcoin/bitcoin#24148: Miniscript support in Output Descriptors

ffc79b8e49 qa: functional test Miniscript watchonly support (Antoine Poinsot)
bfb036756a Miniscript support in output descriptors (Antoine Poinsot)
4a082887be qa: better error reporting on descriptor parsing error (Antoine Poinsot)
d25d58bf5f miniscript: add a helper to find the first insane sub with no child (Antoine Poinsot)
c38c7c5817 miniscript: don't check for top level validity at parsing time (Antoine Poinsot)

Pull request description:

  This adds Miniscript support for Output Descriptors without any signing logic (yet). See the OP of #24147 for a description of Miniscript and a rationale of having it in Bitcoin Core.
  On its own, this PR adds "watchonly" support for Miniscript descriptors in the descriptor wallet. A follow-up adds signing support.

  A minified corpus of Miniscript Descriptors for the `descriptor_parse` fuzz target is available at https://github.com/bitcoin-core/qa-assets/pull/92.
  The Miniscript descriptors used in the unit tests here and in #24149 were cross-tested against the Rust implementation at https://github.com/rust-bitcoin/rust-miniscript.

  This PR contains code and insights from Pieter Wuille.

ACKs for top commit:
  Sjors:
    re-utACK ffc79b8e49
  achow101:
    ACK ffc79b8e49
  w0xlt:
    reACK ffc79b8e49

Tree-SHA512: 02d919d38bb626d3c557eca3680ce71117739fa161b7a92cfdb6c9c432ed88870b1ed127ba24248574c40c7428217d7e9bdd986fd8cd7c51fae8c776e1271fb9

test/functional/test_runner.py

@@ -205,6 +205,7 @@ BASE_SCRIPTS = [
     'wallet_keypool.py --legacy-wallet',
     'wallet_keypool.py --descriptors',
     'wallet_descriptor.py --descriptors',
+    'wallet_miniscript.py',
     'feature_maxtipage.py',
     'p2p_nobloomfilter_messages.py',
     'p2p_filter.py',