home: add quote repost counter and handler

This adds the initial support code for counting and handling
quote reposts.

Eventually we are going to replace all of the event counts by stats
within nostrdb, but we do this in the meantime now.

Signed-off-by: William Casarin <jb55@jb55.com>

damusTests/Mocking/MockDamusState.swift

@@ -49,7 +49,8 @@ func generate_test_damus_state(
                            nav: .init(),
                            music: .init(onChange: {_ in }),
                            video: .init(),
-                           ndb: ndb)
+                           ndb: ndb,
+                           quote_reposts: .init(our_pubkey: our_pubkey) )
 
     return damus
 }