Please provide a description of this PR:
This PR moves all remaining ConfigStoreController implementations to using KRT and adds a KrtCollection method to ConfigStoreController to allow retreiving underlying KRT collections from the controllers and to ensure all controllers are really KRT-based.
This should ease construction of additionaly KRT layers on top of current ConfigStoreControllers or eventually ease moving into a KRT Index such as ambient.

Controllers affeced:

• aggregate: now uses joined collections of the stores it aggregates and uses those collections on Get and List, this allows testing that all other Controller's KRT collections work correctly. removed internal namespacesFilter it was unused.
• memory: removed concept of SyncController, now all controllers are async, since KRT is async. now uses backing KRT collections and a custom syncer we mark as synced when Run is called, this allows most of our test cases to continue to work without major changes.
• file-store: now internally uses memory controller and it's "static" namespace filter is applied on mutation methods.
• crdclient: remove mutex over internal store, should no longer be necessary.
• gateway: added new GatewayConfigs collection which stores valid gateway configs and changed some collections to be config.Config instead of *config.Config to be more compatible with ConfigStoreControllers and it also allows us not to transform the returned values from the collections.
• analysis: removed no longer needed dfCache wrapper since our internalStore is now a memory.Controller.
• mcp-xds: this controller internally uses memory.Controller.