The `msapplication` tile configuration serves no purpose now, so the
`browserconfig.xml` it points at, the five tile images and the two meta tags
in `index.html` are removed together.
`shared-docs/icons/twitter.svg` is also unused, left behind when the footer
moved to X and Bluesky. Its three siblings in that directory are all still
referenced.
(cherry picked from commit a67d4027e2)
1. The WebGL animation on the home page is completely removed.
2. A new animation processor/player is implemented and added to `adev` web app.
3. A new CSS+JS-based animation substitutes the existing WebGL one.
PR Close#59865
Keep theme constants in sync betwee index.html file and theme manager. Move versions config static data to their own file, and replace the deprecated toPromise() api with the new firstValueFrom() api
PR Close#55234
Kam