Rename SCA into Compliance

With the aim to organize the code by features, it will be nice to rename the SCA module to Compliance because it is more related to the feature name and not to the team which is developing the feature.

This issue is extracted from this discussion

what is needed to be renamed:

1. ee/app/models/sca.rb
2. ee/app/models/sca/license_compliance.rb
3. ee/app/models/sca/license_policy.rb

and related test files.