Add "Admin" tab to the registrar console

This tab will set the "allowedTlds", but might have other functionality in the
future.

It is based on (branches from) the security-settings tab, because I'm copying the functionality of the "whitelisted IPs" to the "allowed TLDs": they are both lists of "arbitrary" strings that you can remove from and add to.

There are a lot of moving parts in this CL, because of how all the different elements need to interact, and how intertwined they are (for example, we need to disable the admin-settings view for non admins both in the soy and in the JS code)

It's really time to refactor the console given all we've learned... :/

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=220373443

java/google/registry/ui/css/BUILD

@@ -24,6 +24,7 @@ closure_css_library(
 closure_css_library(
     name = "registrar_lib",
     srcs = [
+        "admin-settings.css",
         "contact-settings.css",
         "contact-us.css",
         "dashboard.css",

java/google/registry/ui/css/admin-settings.css

@@ -0,0 +1,58 @@
+/** Admin Settings */
+
+div#tlds div.tld {
+  width: 209px;
+}
+
+#newTld {
+  width: 187px;
+  margin-left: 0.5em;
+}
+
+div#tlds div.tld input,
+div#tlds div.tld button[type=button] {
+  height: 27px;
+  line-height: 27px;
+  background: #ebebeb;
+  vertical-align: top;
+  border: none;
+  border-bottom: solid 3px white;
+}
+
+div#tlds div.tld input {
+  width: 169px;
+  margin: 0;
+  padding: 0;
+  color: #555;
+  padding-left: 5px ! important;
+}
+
+div#tlds.editing div.tld input[readonly] {
+  margin-left: 0.5em;
+}
+
+div#tlds.editing div.tld button[type=button] {
+  display: inline-block;
+  float: right;
+  margin-left: -2px;
+  width: 30px;
+  min-width: 30px;
+  height: 30px;
+  color: grey;
+  font-size: 1.1em;
+}
+
+div#tlds.editing div.tld button[type=button]:hover {
+  -webkit-box-shadow: none;
+  -moz-box-shadow: none;
+  box-shadow: none;
+}
+
+div#tlds.editing div.tld button[type=button] i {
+  font-style: normal;
+}
+
+div#tlds.editing .kd-errormessage {
+  margin-left: 0.5em;
+}
+