Revert "Splitting poller-configuration in different files using XML entity type definition. Regarding to NMS-5692"

I CapsdIntegrationTests failed. They try load the relativ path of the entity types from opennm-services/etc. I tried to give absolute path as ${install.dir.etc} but the variable will not be resolved during the test.

This reverts commit ee7001954d67f2bdb89cc9c280e89dd737e422a9.