Add Truffle adapter

[kanej]

Taken from feedback: NomicFoundation/hardhat-vscode-feedback#4

Currently, we only show compilation errors for Hardhat projects. Different tools can compile the same codebase differently, leading to different compilation errors. For example, they may choose to use a different version of solc for a certain source file.

We need to detect when a project is using Truffle and get the compilation errors based on its compilation pipeline, ideally without reimplementing its logic.

[kanej]

We have added an adapter structure that allows other projects (other than hardhat) to be used from the language server.

Support for truffle consists of providing an implementation for this adapter that matches the truffle project structures.