Build system enhancements

[kanej]

The build system in Hardhat 3 demonstrates our new Solidity import resolution capabilities, include our support for solc remappings.

Before we consider it production ready we have the identified further enhancements, captured in this ticket.

TODO

• Robustness improvements in the compiler downloader #5990
• Hardhat 3 Build System Integration testing and cleanup #5989
• Compilation caching in the local file system #5991
• Implement build infos compilation #5998
• Refinement of import resolution #5995
• npm package export support within Solidity import resolution #5992
• Build system testing #5997
• Add hooks to build system #5996
• Use wasm for all production build profile builds #5993