This worklog implements the following main changes:

1. Modify cmake files, do not build partitioning engine.
2. Remove files implementing the partitioning engine.
3. Remove some mtr tests using non-native partitioning.
4. Rewrite some mtr tests to use native partitioning.
   Various adjustments necessary, e.g. regarding EXPLAIN
   output.
5. Introduce error handling at the SQL layer to fail
   if using partitioning related DDL statements for
   engines not supporting it natively.
6. Remove reference to the DB_TYPE_PARTITIONING_DB
   internally, but keep the enum entry to avoid
   disturbing other values.
7. Add an mtr test testing the error handling.
8. Add an mtr test to check for regressions in support
   for partitioning in ndb.
9. Copy comments from storage/partition/ha_partition.*
   to sql/handler.*, include/my_base.h etc.