Stop passing ReviewDb, etc. to ChangeData methods

Many methods that are intended for lazy initialization take a
ReviewDb, and some take other helper objects such as
GitRepositoryManager. This achieves the intended lazy-loading behavior
but requires a lot of injection of dependencies into callers, and may
become untenable as lazy loading of ChangeData requires more helpers.

Instead, since after all this is Java, construct ChangeData with a
Factory. This is subtle because it is used from a lot of places that
need control over which ReviewDb handle to pass in, so the factory
methods still need to take a db. ChangeData objects are still intended
(i.e. safe) for use only by one thread, so having a single ReviewDb
instance stored for the lifetime of the ChangeData should be fine. We
just need to be careful about which we pass in, particularly in a
place like ChangeIndexer.

As a side effect, clean up some other injection, particularly in the
predicate class hierarchy.

Change-Id: I52e1eb2a76788c12dd95767e89095ab80df7e1cc

gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteReviewer.java

@@ -103,7 +103,7 @@ public class DeleteReviewer implements RestModifyView<ReviewerResource, Input> {
     } finally {
       db.rollback();
     }
-    indexer.index(rsrc.getChange());
+    indexer.index(db, rsrc.getChange());
     return Response.none();
   }