Solidity source map parser

[mattsse]

Is your feature request related to a problem? Please describe.
source mapping is provided as a String in the ethers-solc Bytecode object, it'd be nice if there were support for parsing this into a real source map object

Additional context
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Source mapping format
https://docs.soliditylang.org/en/v0.8.10/internals/source_mappings.html