Remove prevention of autofocus when no prior focus was done, add warnings.

Summary:
This differential removes a safeguard on preliminary focus which is not always needed in the current state of the Focus module.
The original code prevented the auto-focus method from starting without prior manual focus done at least once.
This safeguard was here to prevent the situation where the optical train would be too far from the focal plane to allow star detection.
In any case, it does not solve any particular problem, and gets in the way of the Scheduler when it starts the observatory by itself.

This differential also adds a warning log about having a periodic or HFR refocus procedure set in Capture while no Focus step is set for the Scheduler job.

Test Plan:
Close and reopen KStars, create a very simple scheduler job with only the focus step selected, and execute it.
Without the change, the focus step outputs the message "Manual scheduler focusing is not supported. Run autofocus process before trying again.".
With the change, the focus step doesn't output that message and proceeds to auto-focus.

Reviewers: mutlaqja, wreissenberger

Reviewed By: mutlaqja

Subscribers: kde-edu

Tags: KDE Edu

Differential Revision: https://phabricator.kde.org/D15436