Migrate documentation website to docfx

[banchan86]

This PR migrates the documentation website to docfx to:

• Simplify long-term maintenance through automatic API generation
• Leverage the Bonsai editor's context menu help feature
• Enable workflow containers for easy copying of Bonsai workflows in tutorials and articles

Additionally, it updates the site content to:

• Add documentation for new operators
• Remove outdated and duplicated links and information (e.g., newsletter, publication)
• Rearrange content in the manual to eliminate redundancy
• Reword article titles for greater clarity

Finally, the PR includes site optimizations to improve performance:

• Convert .gif files to .webp format, achieving faster loading times with a ~90% reduction in file size

Currently, this PR is a draft as there are several PRs that need to be finished or merged:

• Add XML documentation comments for site migration to docfx #32
• Patch to support IncludeWorkflow operators bonsai-rx/docfx-tools#17
• Add API template bonsai-rx/docfx-tools#9
• Add API TOC categories template bonsai-rx/docfx-tools#7

An online preview of this PR is available at:
https://banchan86.github.io/BonVision_env_dev/

[banchan86]

On hold as there are significant problems with the importing of IncludeWorkflows, especially in pulling information from external types (like Bonsai packages or Bonsai Core). Goncalo is exploring alternative solutions for docfx in general by going through the C# plugin route.