In my scene, We need to specify databases that are excluded to synchronize to doris,
like some databases store temporary table.
Since #17803 introduce `specified_database_list` to specify 'include databases',
this pr introduce new config `exclude_database_list` to specify 'exclude databases',
and rename `specified_database_list` to `include_database_list` for naming symmetry.
BTW, when `include_database_list` and `exclude_database_list` specify overlapping databases, `exclude_database_list` would take effect with higher privilege over `include_database_list`.
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