Closes #504 AVIF support

[Tabrisrp]

Description

Add AVIF support in the plugin

Closes #504

Documentation

User documentation

Explain how this code impacts users.

Technical documentation

Explain how this code works. Diagram & drawings are welcomed.

Type of change

Delete options that are not relevant.

• [ ] New feature (non-breaking change which adds functionality).
• [ ] Bug fix (non-breaking change which fixes an issue).
• [ ] Enhancement (non-breaking change which improves an existing functionality).
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as before).

New dependencies

List any new dependencies that are required for this change.

Risks

List possible performance & security issues or risks, and explain how they have been mitigated.

Checklists

Feature validation

• [ ] I validated all the Acceptance Criteria. If possible, provide sreenshots or videos.
• [ ] I triggered all changed lines of code at least once without new errors/warnings/notices.
• [ ] I implemented built-in tests to cover the new/changed code.

Documentation

• [ ] I prepared the user documentation for the feature/enhancement and shared it in the PR or the GitHub issue.
• [ ] The user documentation covers new/changed entry points (endpoints, WP hooks, configuration files, ...).
• [ ] I prepared the technical documentation if needed, and shared it in the PR or the GitHub issue.

Code style

• [ ] I wrote self-explanatory code about what it does.
• [ ] I wrote comments to explain why it does it.
• [ ] I named variables and functions explicitely.
• [ ] I protected entry points against unexpected inputs.
• [ ] I did not introduce unecessary complexity.
• [ ] I listed the introduced external dependencies explicitely on the PR.
• [ ] I validated the repo-specific guidelines from CONTRIBUTING.md.

Observability

• [ ] I handled errors when needed.
• [ ] I wrote user-facing messages that are understandable and provide actionable feedbacks.
• [ ] I prepared ways to observe the implemented system (logs, data, etc.).

Risks

• [ ] I explicitely mentioned performance risks in the PR.
• [ ] I explicitely mentioned security risks in the PR.

[Mai-Saad]

Notes [WIP]: 1- Bulk optimization notice displayed when enable/disable create AVIF (When enable AVIF, despite of having 4 images in media library, AVIF was created for single image and media progress was stuck at 50% till we reoptimize any image, it will stop . @piotrbak is there any need to show progress in bulk optimization once enable AVIF?) => on trunk, was only displayed when click bulk optimization Recommendation:

• no need for bulk optimization notice as we are only generating AVIF and not re-optimizing all images
• even if we agreed to display the notice, it shouldn't be on plugins/post/users... pages

[Mai-Saad]

Related initial test plan https://wpmediaqa.testrail.io/index.php?/runs/view/820&group_by=cases:section_id&group_order=asc