Updates UI code so that we can enable the asset UI for specific ID types by default, i.e. irrespective of the "Extended Asset Browser" experimental feature.
Mark as Asset and Clear Asset are always visible in the Outliner context menu now, but are grayed out if not applicable and show a disabled hint in the tooltip.
Also enables Materials and World assets by default. More for testing, should be committed separately.
Open Issue:
With this it will be possible to mark regular actions as assets, even if they were not created as poses. Should we deal with that differently?
