Gui: Update usability enhancements to ProDark theme

[turn211]

forum thread: https://forum.freecadweb.org/viewtopic.php?f=34&t=55134

LineEdit, QComboBox ans QListView color enhancements for easier editing useablity. Bim View Manager Icon separation and background transparency. HyperLinks color changed in line of https://forum.freecadweb.org/viewtopic.php?f=34&t=55844&start=10

• Your pull request is confined strictly to a single module. That is, all the files changed by your pull request are either in App, Base, Gui or one of the Mod subfolders. If you need to make changes in several locations, make several pull requests and wait for the first one to be merged before submitting the next ones
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And please remember to update the Wiki with the features added or changed once this PR is merged.
Note: If you don't have wiki access, then please mention your contribution on the 0.19 Changelog Forum Thread.

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[luzpaz]

This should also probably get merged in v0.19