Feature: JSON Compiler Interface

I am sure you are aware that Solidity has a JSON based compiler interface, called the "Standard JSON I/O". Documentation [here](https://docs.soliditylang.org/en/v0.8.6/using-the-compiler.html#compiler-input-and-output-json-description). This JSON schema has a `language` field, which we already utilise to select a Solidity or Yul mode.

I think it would be nice if Fe could adopt this schema as well. This could help in having an easier integration with Remix or other tools. As far as I know, most frameworks (including Hardhat, Truffle, etc.) support it.

I suggest to use `Fe` for the `language` field, but also consider using the schema as the `Solidity` target.

Review the linked Solidity Standard JSON I/O description and the existing language-mode handling mentioned in the issue. Define the supported input and output behavior and the required tests before implementation; done means the agreed schema works for Fe and supports the intended Remix or framework integration.

Written by the indexing model from the issue text.