[FL-3662] Do not remove file when renaming to itself

[gsurkov]

What's new

• Enchanced checks for storage_common_remove() function.
• Add storage_common_equivalent_path() function.
• Renaming a file to itself always succeeds.
• Renaming a directory to itself or to a subdirectory of itself always fails.
• Overwriting a regular file with a directory always fails.
• Per-storage support for different case behaviour.
• Update storage.h docs.

Verification

1. Access Flipper's filesystem via an RPC client.
2. Try renaming a directory to the name of an already existing file. The operation should fail with FSE_INVALID_NAME error.
3. Repeat step 2, but change the case of some characters in the name. The result should be the same.
4. Try renaming a directory to the same name. The operation should fail with FSE_INVALID_NAME error.
5. Same as step 3, but in relation to step 4.
6. Try renaming a file to the same name. The operation should succeed.
7. Same as step 3, but in relation to step 6.

Checklist (For Reviewer)

• PR has description of feature/bug or link to Confluence/Jira task
• Description contains actions to verify feature/bugfix
• I've built this code, uploaded it to the device and verified feature/bugfix

[github-actions]

Compiled f7 firmware for commit 3d78e7f0:

• 📦 Update package
• 📥 DFU file
• ☁️ Web/App updater