non-x Preference is deprecated

[Xavron]

The problem

Class Preference is deprecated. This has a lot of annoying marks filling up the screen.

Can just switch to androidx (with a few quick fixes to do past the code changes below) or whatever else as desired.

eg...

implementation 'androidx.preference:preference:1.2.1'

import androidx.preference.Preference;
import androidx.preference.CheckBoxPreference;
import androidx.preference.EditTextPreference;
import androidx.preference.ListPreference;
import androidx.preference.MultiSelectListPreference;
import androidx.preference.PreferenceManager;
import androidx.preference.PreferenceScreen;
import androidx.preference.TwoStatePreference;

Possibilities

• Androidx changes are fully implemented. This is be used for the pull request.

• Can of course fully rework the UI layout to something completely different and have it look very much the same.

Edit: Pull request created #248 . If it passes, can close this and #247 (if that also passes).