Light mode: more fixes & cleanup:

- Remove lots more unused files
- Make light mode toggles for Exchange and Wallet images
- Change layout for exchanges and wallets to work better at some screen
  widths (between mobile and full 1080p)
- Fix light mode styles for some dev tools, carbon calculator, Edit
  button, footer, etc.

styles/_dev-tools.scss

@@ -36,6 +36,7 @@
 
 .page-tx-sender .input-group .form-control {
   flex: 1 1 20%;
+  height: auto;
 }
 
 .bootstrap-growl {
@@ -99,3 +100,11 @@
     margin: 0 !important;
   }
 }
+
+.rpc-tool .main {
+  h1::before, h2::before, h3::before {
+    // These aren't anchors, and the placement of the anchor fix thing
+    // causes things above them to be unclickable
+    display: none;
+  }
+}