Feature/contextual stub buttons

[dukeofharen]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: N/A

What is the new behavior?

• Three new buttons were added to the stubs overview: enable stubs, disable stubs and delete stubs.
• These buttons either enable, disable or delete the stubs that are currently on the screen. That means if you fill in a filter, only those stubs are affected.
• Press the "Yes" button when pressing "Enter" on a modal popup.

Does this introduce a breaking change?

• Yes
• No

Other information