unify resource_* with the configuration_* tables

Currently the templates are saved in the resource_* tables, but, in theory, with some refactoring they coud be folded in the configuration_* .

Benefit: less tables, more coherent api.

Note: the configuration_* tables could be additionally folded in a single one.

Note2: we can use partial unique index for handling the uniqueness https://www.postgresql.org/docs/current/indexes-partial.html