Migrate solidity parsing to slang

[dk1a]

contractToInterface and a couple related files use @solidity-parser/parser
They can be refactored to use @nomicfoundation/slang instead

• I mention the main issue of solidity-parser lacking unparse in fix(common): explicit error in contractToInterface #3660 - this particularly complicates handling static array types
• slang has better architecture, no stateMutability hacks for address payable as in solidity-parser
• better version control - solidity version is just a Parser argument
• semantic analysis for going through the whole project tree much more easily, if that becomes desirable for e.g. system inheritance

I can also do the PR if you approve the change

(not relevant if you intend to move away from solidity parsing entirely, though I'd be curious about the new approach)