The .ui files are all GPL-3.0-or-later style, but it's
slightly difficult to keep licensing information in them:
it's XML, so an XML comment might work, but there's no
guarantee that safe/load will preserve them.
Put the SPDX tags in the <author> tag, so that it's visible
in Qt Designer.
- make the HostName textbox just a view on the Config's HostName
- make the username and login textboxes view onto Config
- query the Config rather than the UI for job data
- the explanations under and around the boxes is noisy,
hard to size correctly (viz. issue #1202)
- use tooltips in almost-all fields instead
- add placeholder text to be more suggestive
