Check Namespace Adding to Correct Repository

[lharzenetter]

In case a namespace is added during the creation of a new TOSCA definition, it should be automatically added to the workspace but not to another repository. This must be tested and verified. The implementation for adding a new namespace to a specific repository is currently only available in the administration, see https://github.com/eclipse/winery/pull/679/commits/f65a7c29875fe17abe0183c18370bd8d3eb623dd