feat: let LSP always work in a Noir workspace if there's any

[asterite]

Description

Problem

Resolves #5460

Summary

Sorry for the many commits, the PR was stacked on top of other PRs. Here's the first relevant commit: link

Before this PR, LSP "find all references" and "rename" worked like this:

1. Find what's in the cursor location. That could either be a definition, or it could be a reference to a definition (or, well, nothing)
2. If it's a reference, go to the definition (otherwise keep the definition)
3. From the definition, find all references to that definition.

That works well, but that always happened in a single Package. So, if you ran this in a Package A, but there's Package B that depends on Package B, references in B weren't returned (they can't be seen from A!)

To solve this, a few things were done here:

1. First, the old LSP code always used the Nargo.toml file nearest to a file. That means that it would never find workspace. Now we continue searching a Nargo.toml upwards even if we find one, up until the LSP root directory, and keep the last one (if we find anothe one it's likely a workspace Nargo.toml). With this change it means that when opening any file in a package, if that package is included in a workspace (and that workspace is in the editor) we actually invoke "nargo check" on each package in the workspace, not just in the package where the file is. That's the first step in actually tracking everything in the workspace.
2. Second, when searching for references, we search for references in all packages. To do this we first find a definition in the current package, then search references to that definition in all other packages.

I believe that with this, the LSP features are now much more usable! Searching a type, a struct member, an alias, a global, etc., anywhere, will always yield the same results. This is useful, and necessary, if, say, we want to rename a type or a member that's used across the workspace: changing that only in some packages wouldn't be (that) useful.

Here it is in action, using https://github.com/vlayer-xyz/monorepo to try it out:

lsp-workspace-references.mov

Here StorageWithinBlock is defined in a lib project which has no dependencies to other packages in the workspace. However, other packages depend on it, for example get_storage, and those references are found.

Note: the first commit is a refactor so it's easier to see where references to specific things are tracked. With just add_reference it was kind of hard to debug when something didn't work well for a specific thing (for example globals). It also removes some redundancy because in some cases the is_self_type boolean doesn't make sense.

Additional Context

None.

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

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