Sorted the icon folders by source and added ico/README.md

Each folder now holds icons from one source: qet/ for QET's own SVGs,
breeze/ for KDE Breeze (with breeze/added/), flags/, colors/, and
themes/ for script output (with themes/generated/). The unused
128x128/terminalstrip.svg is removed. The generator, qrc files,
qeticons.cpp and ico/copyright follow the new paths. ico/README.md
lists each folder's source, script and license.

Part of #1269.

ico/breeze/added/16/preferences-desktop-user.svg

@@ -0,0 +1,19 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16">
+  <!-- Drawn for QElectroTech on Breeze's 16 pixel grid, after Breeze's 22 and
+       32 pixel preferences-desktop-user; Breeze has no 16 pixel drawing. -->
+  <defs>
+    <linearGradient id="a" x2="0" y1="15" y2="1" gradientUnits="userSpaceOnUse">
+      <stop offset="0" stop-color="#197cf1"/>
+      <stop offset="1" stop-color="#20bcfa"/>
+    </linearGradient>
+    <linearGradient id="b" x2="0" y1="12" y2="4" gradientUnits="userSpaceOnUse">
+      <stop offset="0" stop-color="#7cbaf8"/>
+      <stop offset="1" stop-color="#f4fcff"/>
+    </linearGradient>
+  </defs>
+  <circle cx="8" cy="8" r="7" fill="url(#a)"/>
+  <rect x="5" y="4" width="3" height="3" rx="1" fill="url(#b)"/>
+  <path d="M3 12v-1a3.5 3 0 0 1 7 0v1z" fill="url(#b)"/>
+  <rect x="11" y="5" width="2" height="2" rx="1" fill="url(#b)"/>
+  <rect x="11" y="8" width="2" height="4" fill="url(#b)"/>
+</svg>

ico/breeze/added/16/transform-crop.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16">
+  <defs id="defs3051">
+    <style type="text/css" id="current-color-scheme">
+      .ColorScheme-Text {
+        color:#232629;
+      }
+      </style>
+  </defs>
+  <path style="fill:currentColor;fill-opacity:1;stroke:none" class="ColorScheme-Text"
+     d="M2 2h3v3h-3zM3 3v1h1v-1zM12 2h3v3h-3zM13 3v1h1v-1zM2 12h3v3h-3zM3 13v1h1v-1zM12 12h3v3h-3zM13 13v1h1v-1zM6 4h2v1h-2zM9 4h2v1h-2zM6 12h2v1h-2zM9 12h2v1h-2zM4 6h1v2h-1zM4 9h1v2h-1zM12 6h1v2h-1zM12 9h1v2h-1z"/>
+</svg>