Restructure tests, add simulator tests, spot expected failures.

Summary:
This differential restructures test execution to allow use of regular test classes for UI tests of KStars.

A few tests are reworked with additional features:

• Geographical location is set to Greenwich and verified against city database
• Date and time of simulation is set to 2020/01/01 11:00pm and verified
• Clock is set to not run and verified
• Basic test and warn test are removed
• Fixture data is created for Messier objects higher than the horizon at current simulation time
• Slew test is created to point at each fixture in sequence using the Simulators profile
• Various dialog appearing for questions are managed by tests

Tests reveal that:

• There is no definitive UI feedback to end the connection procedure of devices
• There is limited homogeneity on dialogs presented to the end-user (QDialog, KMessageBox, KNotification)
• Ekos unconditionally resumes the simulation clock on startup, and resets its date and time to current system time

Test Plan:
Execute kstars_ui_test, either from the command line or from the QtCreator project run or from the QtCreator test run (check timeout in options)
The test can be executed in a virtual framebuffer X server using "xfvbrun".

Reviewers: KStars, mutlaqja

Reviewed By: KStars, mutlaqja

Subscribers: yurchor, kde-edu

Tags: KDE Edu

Differential Revision: https://phabricator.kde.org/D27678