chore: Try using traits for FileManager [DO NOT MERGE]

[kevaundray]

Description

This removes the need for an actual file manager in the compiler. The compiler instead defines an interface/trait that abstracts this away.

The current impl just copies the methods from FileManager, I'd imagine that we'd want to make the methods less specific to a file system, but for now if this looks good, I think its a future todo, since we rely on being able have segments for what we are calling path.

Problem*

Resolves

Summary*

Additional Context

Documentation*

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• I have tested the changes locally.
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[kevaundray]

Merges in changes from #3846

[kevaundray]

Made a PR to build off of this and it seems that to get a clean API, we need to at the least:

• Not have FileId be an asscociated type for the trait: A lot of places use FileId and so we are forced to make all of those methods and structs generic just because they use FileId.

[kevaundray]

Until a follow-up PR can be built which shows how we would use the FileManager trait in a clean way, I'd be okay with not merging this just yet

[TomAFrench]

I'm going to close this as stale. Handling these merge conflicts will basically require a rewrite anyway.