Merge #11854: Split up key and script metadata for better type safety
9c8eca7 Split up key and script metadata for better type safety (Russell Yanofsky)
Pull request description:
Suggested by @TheBlueMatt
https://github.com/bitcoin/bitcoin/pull/11403#discussion_r155599383
Combining the maps was probably never a good arrangement but is more
problematic now in presence of WitnessV0ScriptHash and WitnessV0KeyHash types.
Tree-SHA512: 9263e9c01090fb49221e91d88a88241a9691dda3e92d86041c8e284306a64d3af5e2438249f9dcc3e6e4a5c11c1a89f975a86d55690adf95bf2636f15f99f92a