Directly specify arcsecond error in Align UI.

Summary:
As part of the align tab, the user enters an accuracy (in arc-seconds) for the error tolerance
in pointing the telescope to the target, but the error value calculated is not currently reported
in the UI. What is currently reported is the DEC d-m-s arc-second difference, and the RA h-m-s
difference (which is not arc-seconds), not the combined arc-second difference.
With this change, the difference in arc-seconds (directly comparable to the user's specification),
followed by the RA and DEC arc-second differences are printed in the UI. It is printed in green
if the specification is met, and red if it is not met.
Screenshot of the UI.
https://drive.google.com/file/d/1EH51G3LosVIT9vLY3nIx1UpH7rsw7tj4/view?usp=sharing

Test Plan:
Run alignment with debug output, see the arcsecond error printed to the debug log console,
note that the errors printed match the values printed in the new Err UI box in Align, and
note that the printing is in red if the error is greater than the tolerance specified in Align,
or printed in green if the error is less.

Reviewers: mutlaqja

Reviewed By: mutlaqja

Subscribers: lancaster, kde-edu

Tags: KDE Edu

Differential Revision: https://phabricator.kde.org/D25114