Remove InMemoryStore option from AerieAppDriver

The InMemory versions of the repositories are either stubs or only defined enough to be used in testing. Therefore, we should remove the ability to initiate Aerie using an InMemoryStore.

- Remove classes that are unused as of this pruning

merlin-server/src/main/java/gov/nasa/jpl/aerie/merlin/server/AerieAppDriver.java

@@ -4,15 +4,11 @@
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 import gov.nasa.jpl.aerie.merlin.server.config.AppConfiguration;
-import gov.nasa.jpl.aerie.merlin.server.config.InMemoryStore;
 import gov.nasa.jpl.aerie.merlin.server.config.PostgresStore;
 import gov.nasa.jpl.aerie.merlin.server.config.Store;
 import gov.nasa.jpl.aerie.merlin.server.http.LocalAppExceptionBindings;
 import gov.nasa.jpl.aerie.merlin.server.http.MerlinBindings;
 import gov.nasa.jpl.aerie.merlin.server.http.MissionModelRepositoryExceptionBindings;
-import gov.nasa.jpl.aerie.merlin.server.mocks.InMemoryMissionModelRepository;
-import gov.nasa.jpl.aerie.merlin.server.mocks.InMemoryPlanRepository;
-import gov.nasa.jpl.aerie.merlin.server.remotes.InMemoryResultsCellRepository;
 import gov.nasa.jpl.aerie.merlin.server.remotes.MissionModelRepository;
 import gov.nasa.jpl.aerie.merlin.server.remotes.PlanRepository;
 import gov.nasa.jpl.aerie.merlin.server.remotes.ResultsCellRepository;
@@ -125,13 +121,6 @@ private static Stores loadStores(final AppConfiguration config) {
           new PostgresPlanRepository(hikariDataSource),
           new PostgresMissionModelRepository(hikariDataSource),
           new PostgresResultsCellRepository(hikariDataSource));
-    } else if (store instanceof InMemoryStore) {
-      final var inMemoryPlanRepository = new InMemoryPlanRepository();
-      return new Stores(
-          inMemoryPlanRepository,
-          new InMemoryMissionModelRepository(),
-          new InMemoryResultsCellRepository(inMemoryPlanRepository));
-
     } else {
       throw new UnexpectedSubtypeError(Store.class, store);
     }

merlin-server/src/main/java/gov/nasa/jpl/aerie/merlin/server/config/Store.java

@@ -1,5 +1,5 @@
 package gov.nasa.jpl.aerie.merlin.server.config;
 
 public sealed interface Store
-    permits PostgresStore, InMemoryStore
+    permits PostgresStore
 {}