multiprocess: Add bitcoin wrapper executable

Intended to make bitcoin command line features more discoverable and allow
installing new multiprocess binaries in libexec/ instead of bin/ so they don't
cause confusion.

Idea and implementation of this were discussed in
https://github.com/bitcoin/bitcoin/issues/30983

Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>

contrib/guix/security-check.py

@@ -126,6 +126,9 @@ def check_ELF_FORTIFY(binary) -> bool:
     # bitcoin-util does not currently contain any fortified functions
     if 'Bitcoin Core bitcoin-util utility version ' in binary.strings:
         return True
+    # bitcoin wrapper does not currently contain any fortified functions
+    if '--monolithic' in binary.strings:
+        return True
 
     chk_funcs = set()