[Meta] Extension addition and removal issues

Moved telephone from add to remove section.

I moved the wrong issue to the completed section

These issues are going to be obsolete with XB and/or display builder, and in the case of the responsive layout builder it seems that the feature isn't necessesary given the lack of contrib solution for that

#3067700: Bring block class module to core →
#2875935: Add Components Module to Drupal Core →
✨ Add field grouping to core Needs work
🌱 [META] Add editable responsive layouts to Drupal core Postponed
#1822950: Add responsive layout builder to core →
#1813910: Add region module to Drupal core (for editable responsive layouts) →

✨ Add field grouping to core Needs work is not going to be handled by XB unless 📌 Refactor the XB field type to be multi-valued, to de-jsonify the tree, and to reference the field_union type of the prop values Active or a similar happens, which is still undecided (and probably some other issues to enable non-XB/structured data uses of field unions in core in their own right even if that issue does proceed).