It's a duplicate of LICENSE env var
**What this PR does**:
Remove OSS_INSTALLATION env var in favour of LICENSE env var. Also, I
refactored features tests a little. From my point of view it makes
little sense to test if all features are disabled or enabled. Better to
test specific use-case (e.g. oss installation).
Also to test that all features are disabled it is needed to set LICENSE
equals cloud license, which makes test confusing.
**Checklist**
- [x] Tests updated
- [ ] Documentation added
- [ ] `CHANGELOG.md` updated