Enable Dynaconf global merge

https://www.dynaconf.com/merging/#global-merge

This ensures that the order in which config files are laoded is irrelevant, and config files cna extend structures from others.

added part::backend type::bug type::feature labels

assigned to @debdolph

created merge request !859 (merged) to address this issue

mentioned in merge request !859 (merged)

assigned to @nik and unassigned @debdolph

closed with merge request !859 (merged)

mentioned in commit 79a33e5c