Clean up GUI text

[vkbo]

Summary:

This PR removes a lot of GUI text. There were a number of redundant tooltips. That is, tooltips that say exactly the same as the GUI element says. That includes every status bar message from hovering over menu entries. Some dialog boxes have been removed or merged with other boxes. In addition, the class name labels have been split into singular and plurals.

Related Issue(s):

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All flake8 checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed