[Frontend] Create a UX bundle: add requirements for Asset Mapper

[jmsche]

Closes #18748.

Hi @weaverryan, could you please have a look at this? Thanks 😄

[jmsche]

Hmm Doctor RST asked me to rename $builder to $container, so I did, but now it wants me to also rename $configurator to $container... This won't work.

The Code Blocks workflow complains about Symfony\Component\AssetMapper\AssetMapperInterface not being available, but I guess I should add this component to https://github.com/symfony-tools/symfony-application?

[javiereguiluz]

@jmsche thanks for reporting all these issues and for fixing them yourself.

About the DOCtor-RST issue, I'll try to fix it in a separate PR. Thanks!