MyISAM used to be the only one to support it, now InnoDB has caught up.
Unless an engine is set specifically in create_table_options,
this will auto-convert existing MyISAM tables to InnoDb.
Fixes#9242
This change also renders a portion of DBSchemaManager irrelevant, that
destructively “fixes” old values. This is in keeping with the
non-destructive principle of dev/build, and some suggestions to move
away from enum fields altogether.
Fixes https://github.com/silverstripe/silverstripe-framework/issues/1387
