Impelement Tests

[zrgt]

Currently no automatic tests and CI/CDs for that are implemented. To improve the software quality we need to implement them.
We can start with the following tests:

• Open AAS Manager
• Open AASX/JSON/XML - Example file
• Navigate through each cell in opened AASX/JSON/XML - Example file
• Open and close edit dialog for each object in in opened AASX/JSON/XML - Example file

Tests need to be implemented and later a Github Action should be configured to run tests on each commit

[monsieuremre]

Now what we have:

• Open a file (or don't, optional)
• Iterating through the elements. If no file is there, then its just empty.
• When it comes to submodels, pop up the add object dialog and add an example object.
• Then delete this object by popping up the delete dialog and pressing ok.
• For other sections open and close the add dialog but dont and any objects. (Shells, files, concept descriptors)

Additionally and optionally, we can choose a filled test file and edit objects there or pop open the edit dialogs.

But for now, we more or less test the very basic functionality of the program with this script.