Code migration of get location by parent location service

[proshantokuet]

Query:
SELECT parent_location_id parent_id,l.id id, split_part(l.name, ':', 1) as name from core.location l WHERE l.parent_location_id=#{parentId,jdbcType=BIGINT}

Github link: server-web/blob/brac-hnpp/opensrp-core/src/main/java/org/opensrp/repository/postgres/mapper/custom/xml/CustomClientMapper.xml