Redesign settings UI in plugin (#886)

assets/images/icons/back.svg

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg width="100%" height="100%" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
+    <path d="M20,11L20,13L8,13L13.5,18.5L12.08,19.92L4.16,12L12.08,4.08L13.5,5.5L8,11L20,11Z" style="fill:white;fill-rule:nonzero;"/>
+</svg>

assets/images/icons/close.svg

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg width="100%" height="100%" viewBox="0 0 24 24" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:1.5;">
+    <g id="Artboard1" transform="matrix(0.0666667,0,0,0.097561,-31,-18.6341)">
+        <rect x="465" y="191" width="360" height="246" style="fill:none;"/>
+        <g transform="matrix(134.328,0,0,102.5,-74228.5,-15214.7)">
+            <g transform="matrix(1.11667,0,0,1,-57.3333,0)">
+                <path d="M551,152L550,151" style="fill:none;stroke:white;stroke-width:0.3px;"/>
+            </g>
+            <g transform="matrix(1.11667,0,0,1,-57.3333,0)">
+                <path d="M550,152L551,151" style="fill:none;stroke:white;stroke-width:0.3px;"/>
+            </g>
+        </g>
+    </g>
+</svg>