Redundancy is redundant :)
Removing unused imports and some variable references
Fixes the issues while editing Variants as developer

Included into this commit:

- Cleanups for duplicated methods
- Removal of the search of variant by per owner.
Now the search is based only on Variant ID, once does
not exist a Variant without an Application
- Change the endpoints to make use of Variant Service
- Fixes for broken tests