Task: make `tools.make_adapter_locks_prv` and related tools use private adapter signatures

[k98kurz]

Task Description

make_adapter_locks_prv currently calls make_adapter_locks_pub under the hood, and make_adapter_witness uses only OP_MAKE_ADAPTER_SIG_PUBLIC.

• Make e2e test for OP_MAKE_ADAPTER_SIG_PRIVATE
• Make new ops if necessary
• Construct actual uses of OP_MAKE_ADAPTER_SIG_PRIVATE and relevant tools
• Make e2e test with both private and public adapter signatures

See https://bitcoinops.org/en/topics/adaptor-signatures/ for more thorough example of how this is supposed to work.