fix: Create FileManager with a root and normalize filenames against it

[phated]

Description

Problem*

Resolves #1869
Resolves #1599 (this can still be cleaned up a bit by taking a reference & adding a lifetime to context)

Summary*

This changes the FileManager so that it requires a root when constructed. It then resolves the root against filenames passed to add_file and uses a custom normalize_path function to resolve . and .. in the resulting file paths. This avoids the canonicalize function which goes out to the filesystem and is unimplemented!() in WASM.

Since the FileManager must be constructed with a root, I've also removed the Default deriver and constructed Context manually in each location we need one.

I've tried to think through all of the ramifications of this change, but I probably missed something that @TomAFrench will catch. Nevertheless, I think this is a step in the right direction because we aren't reliant on the current_dir of the running process.

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[Maddiaa0]

I really appreciate you doing this @phated, this looks good to me

[TomAFrench]

I'm getting test failures if I swap out normalize_path for std::fs:canonicalize when using my alternative impl which only normalizes files which should exist. This seems odd so will going to take a little bit of an extra look before approving.

[TomAFrench]

This looks good to me once all the conflicts are fixed. Took a look at addressing this myself but I'm not sure what the deal is with lsp_hacky and don't want to use an incorrect path in there and break things.

[kobyhallx]

LGTM