Old pages app can still link to old categories app, so it still needs to be kept, but hidden, until we unbundle old pages app. 

If old pages app is not present in CE, we can remove the dependency by default. Not from dx core though due to above.

We can try to remove it from CE and see if some forgotten dependency is there. If not, can stay gone.

Part of testing should cover:

• in old pages app add a component that links to categorization and do some saving/opening 
• same in new pages app
• other apps where categories may be used (tours, ..?)