Migrate persistent sites and site instance.
A large number of changes relating to the infoschema rewrite:
+ Remove use of annotations.
+ Convert all nonsynthetic infoschema show/info/mysql to use queries routed through the engine
+ Some synthetic infoschema show commands (i.e. show create database) have also been reimplemented
  as sql queries.

Still broken:
+ upgrade, TemporaryTableTest.