Fix parsing for interfaces and some other minor updates

[anzoman]

This PR will:

• add fixes for TOSCA interface operations (see #237)
• add more checks for Standard and Configure TOSCA interface operations
• update outputs for execution of primary implementation artifacts
• update file comparison within template comparer
• remove CI/CD run for Python 3.7
• remove the remaining targeted TODOs

Fixes #237.

[anzoman]

@alexmaslenn thanks, I forgot to check that and have now incorporated your suggestion in this PR.