Most properties of test suite and test suite repository were by mistake set with type "lines" instead
of strings. Due to this, constraints where not working (for checking missing properties). Also, workflow
was not properly set to check constraints. So at the end, most constraints were ignored.

Change properties from type lines to type string. Add test for constraitns. Add compatiblity code
to do transparent migration of existing tests suites and test suite repositories.

Remove obsolete properties and constraints.