Add qss theme from qtum core

[akshaynexus]

This is a attempt at Adding qtum-core wallet styling to the electrum wallet.
Not sure if all themes should be supported in this like the core walelt or just one would suffice.

[icodeface]

thanks for contributing, but got some xxx does not have a property named "showGrid", hope this can be fixed, and make it an optional choice in "Preference" => "General" => "Color theme" will be better.

[akshaynexus]

Ok

[akshaynexus]

Added theme selection options to ui,needs the showgrid fixes,but do test the ui and let me know if any changes are required
if not then ill proceed to fix the showgrid issues

[icodeface]

good job, most of them are good, just some details need to adjust.
The alignment of right buttons inside the address edit in "Send" page are affected, and I think we can keep border-radius of QLineEdit the original size.

[akshaynexus]

Will update the themeswitcher to Update the theme without restarting,looks like electrum stuck with on start theme switching for some reason even when on teh go change of stylesheets is possible

[akshaynexus]

Let me know if any changes is needed.

[icodeface]

Hi , @akshaynexus
please check:

good job, most of them are good, just some details need to adjust.
The alignment of right buttons inside the address edit in "Send" page are affected, and I think we can keep border-radius of QLineEdit the original size.

and there are some xxx does not have a property named "showGrid" warnings when using "Qtum Dark"

[akshaynexus]

Alright,will do the required updates soon.

[davidmerwin]

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