feat: Add GazeDataFrame.apply()

Description

This creates a facade method that can be used for both gaze transformations and event detection.

Implemented changes

[x] Add GazeDataFrame.apply()

Type of change

[x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

[x] Copied contents from three event detection test cases
[x] Copied contents from three transformation test cases

Checklist:

[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Any dependent changes have been merged and published in downstream modules
[x] I have checked my code and corrected any misspellings

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (4de6d34) 100.00% compared to head (7372d91) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #558 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 49 49 Lines 2164 2176 +12 Branches 532 536 +4 ========================================= + Hits 2164 2176 +12 ``` | [Files Changed](https://app.codecov.io/gh/aeye-lab/pymovements/pull/558?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aeye-lab) | Coverage Δ | | |---|---|---| | [src/pymovements/events/detection/\_library.py](https://app.codecov.io/gh/aeye-lab/pymovements/pull/558?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aeye-lab#diff-c3JjL3B5bW92ZW1lbnRzL2V2ZW50cy9kZXRlY3Rpb24vX2xpYnJhcnkucHk=) | `100.00% <100.00%> (ø)` | | | [src/pymovements/gaze/gaze\_dataframe.py](https://app.codecov.io/gh/aeye-lab/pymovements/pull/558?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aeye-lab#diff-c3JjL3B5bW92ZW1lbnRzL2dhemUvZ2F6ZV9kYXRhZnJhbWUucHk=) | `100.00% <100.00%> (ø)` | | | [src/pymovements/gaze/transforms.py](https://app.codecov.io/gh/aeye-lab/pymovements/pull/558?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aeye-lab#diff-c3JjL3B5bW92ZW1lbnRzL2dhemUvdHJhbnNmb3Jtcy5weQ==) | `100.00% <100.00%> (ø)` | |

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aeye-lab / pymovements