fix(server): improve logging for deleted file

[tessus]

Description

This change converts a path to a string.

Motivation and Context

Before

<TIMESTAMP> INFO rustypaste::server: deleted file: Path("file-to-delete.txt")

After

<TIMESTAMP> INFO rustypaste::server: deleted file: "file-to-delete.txt"

How Has This Been Tested?

• manually
• fixtures (no new tests)
• cargo test (no new tests)

Changelog Entry

### Changed

- Improved server side logging when deleting a file

Types of Changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation (no code change)
• [ ] Refactor (refactoring production code)
• [ ] Other

Checklist:

• [x] My code follows the code style of this project.
• [ ] I have updated the documentation accordingly.
• [x] I have formatted the code with rustfmt.
• [x] I checked the lints with clippy.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (8de2450) 70.11% compared to head (40559f7) 70.11%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #235 +/- ## ======================================= Coverage 70.11% 70.11% ======================================= Files 11 11 Lines 609 609 ======================================= Hits 427 427 Misses 182 182 ``` | [Flag](https://app.codecov.io/gh/orhun/rustypaste/pull/235/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Orhun+Parmaks%C4%B1z) | Coverage Δ | | |---|---|---| | [unit-tests](https://app.codecov.io/gh/orhun/rustypaste/pull/235/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Orhun+Parmaks%C4%B1z) | `70.11% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Orhun+Parmaks%C4%B1z#carryforward-flags-in-the-pull-request-comment) to find out more.

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