Size regression in `main.js` bundle caused by standalone component migration

[ybnd]

Describe the bug
Looks like migrating to standalone components in #2750 increased the size of our main.js bundle by about 30kB.

While this is not a significant increase, it's a bit counter-intuitive since the claim is that standalone components should improve the bundle structure.

Here are some improvements we can make:

• Move route-specific components out of ListableModule and reduce the number of imports
  • Mainly: Standalone Item pages, MyDSpace components
  • This can easily save us ~60kB (gz)
  • A little fragile though: we've already seen that overwriting these components in themes causes regressions. We can propose a workaround to mitigate this.
• Make dynamic form code lazy again
  • Dynamic forms are only used on a select number of routes, many of which are not even accessible by anonymous users, so it would be good to keep them out of the main bundle
  • Looked into this for a short while, and it's not as easy but could save us another ~40kB (gz)

[ybnd]

Note: for the numbers above I compared a8f31948bc9 and 41eccbbfe15, the "potential gains" from splitting up ListableModule may be different after the Angular 16 upgrade

[ybnd]

Just re-checked: main.js is ~600kB currently (down from ~670kB)
But the potential size reductions from ↑ still apply.

[ybnd]

Looks like this has become more of a problem now; the main.js bundle is now around 820 kB gzipped.

More than 200 kB of potential savings to be had in terms of code that's shipped in the main bundle but only used on some of our pages:

• Geospatial: 62 kB
• Submission-related: 60 kB
• Search & browse: 48 kB
• Item pages: 25 kB
• MyDSpace: 15 kB