Increase route build speed.

Problem/Motivation

Currently during a route rebuild the module loops through each view, then gets the entity type and bundles for the view, and the grabs the resource names for each entity/bundle combination:

        $resource_types = array_map(function ($bundle) use ($entity_type) {
          return $this->resourceTypeRepository->get($entity_type, $bundle)->getTypeName();
        }, $bundles);

During normal usage this works fine, but during database updates it causes a massive slowdown. If a module does any sort of update that requires a route rebuild, the module can take over 45 minutes to complete on a moderately sized site (46 views with `13 content types in my case). This is because during database updates the cache backend is switched to UpdateBackend, which prevents cache writes. This makes it so that each call to the resourcetype repository involves it rebuilding its cache, which slows down things considerably.

Proposed resolution

The easiest fix for now would be to hold onto the $resources_types returned for each entity type, and use them for any other views that share that entity type. This way if you have 10 views that are node based, for example, you're only paying once for the performance hit to get the resources names. During normal use it doesn't make a huge difference but during database updates you get a massive performance increase. That's what the attached patch does.