New: Darkmode

* New: Native Theme Engine

Co-Authored-By: Zak Saunders <thezak48@users.noreply.github.com>
(cherry picked from commit 2291f3e00eb2ff9268a0b2f49da8dde82ee13c04)

* Update CSS for themes

* Fixup CSS values

* Fixup remove duped Color-Impaired setting

* Fixup Link Colors

Co-Authored-By: Qstick <qstick@gmail.com>

frontend/src/Components/CircularProgressBar.js

@@ -1,6 +1,5 @@
 import PropTypes from 'prop-types';
 import React, { Component } from 'react';
-import colors from 'Styles/Variables/colors';
 import styles from './CircularProgressBar.css';
 
 class CircularProgressBar extends Component {
@@ -132,7 +131,7 @@ CircularProgressBar.defaultProps = {
   containerClassName: styles.circularProgressBarContainer,
   size: 60,
   strokeWidth: 5,
-  strokeColor: colors.readarrGreen,
+  strokeColor: '#00A65B',
   showProgressText: false
 };