Update DbSearch classes for Postgres and SQLite.

Signed-off-by: Norv <a.w.norv@gmail.com>
Move support_ignore() method to the database adapter.

Signed-off-by: Norv <a.w.norv@gmail.com>
'db_search_query' -> search_query() in DbSearch classes.

Signed-off-by: Norv <a.w.norv@gmail.com>
Refactor the rest of the DbSearch methods, initialization, and calls to.

Signed-off-by: Norv <a.w.norv@gmail.com>