feat(filesystem): implement AsyncFileSystem trait for fatfs

[Koichi98]

Description

Overall summary of the series of PRs implementing AsynFileSystem trait

This series of PRs introduces a filesystem trait which fatfs then implements, enabling the use of an in-memory file system from applications. The filesystem trait is specifically an AsyncFileSystem trait, based on a no_std port of rust-vfs to awkernel. File systems implementing this trait can indirectly leverage various file operations provided by AsyncVfsPath.

Prerequisites for Merging

Before merging this PR, the following related PRs, which contain changes extracted from this one, will be merged:

• Introduce Arc to fatfs
• Integrate rust-vfs source code into awkernel
• Port rust-vfs to no_std and remove unnecessary parts

Outstanding To-Do Items

The following items are directly related to this PR but are not covered by its current changes:

• Correct time information retrieval in metadata method: Currently, a NullTimeProvider is used during fatfs instance creation, which needs to be addressed to obtain correct time-related information.
• Implement a wrapper layer with a mount table: Presently, file operations are performed by calling new_in_memory_fatfs on AsyncVfsPath to get an AsyncVfsPath instance representing the root directory. Currently, I'm planning to implement a wrapper layer with a mount table. This will allow users to perform file operations without needing to know the specific file system, as the wrapper will internally return the appropriate AsyncVfsPath for a given file path.

Related links

How was this PR tested?

Notes for reviewers