Features/tsc merkle proofs (#1056) * Add tsc merkle proof endpoint see: https://tsc.bitcoinassociation.net/standards/merkle-proof-standardised-format/ * Fix pylint warnings * Fix AttributeError in pytest causing tests to fail instead of skipping - Error message: "'MarkDecorator' object has no attribute 'lower'" * Add tsc_format option to Merkle.branch_and_root() which adds asterixes in place of "duplicate hashes" - SessionManager._merkle_branch now always returns branch, root and cost - Add unittest coverage for the "blockchain.transaction.get_tsc_merkle" endpoint - Add MacOS-specific installation for plyvel / leveldb to fix a long-standing issue with test_compaction failing in Azure. This required leveldb 1.22 as leveldb v 1.23 runs into issues with "Symbol not found: __ZTIN7leveldb10ComparatorE" * Add documentation for TSC merkle proof format endpoint - Reorganise into 4 separate unittests * Account for all cost estimates (TSC merkle endpoint)