[feature] New user sign-up via web page (#2796)

* [feature] User sign-up form and admin notifs

* add chosen + filtered languages to migration

* remove stray comment

* chosen languages schmosen schmanguages

* proper error on local account missing

web/template/confirmed_email.tmpl

@@ -0,0 +1,30 @@
+{{- /*
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/ -}}
+
+{{- with . }}
+<main>
+    <section aria-labelledby="confirmed">
+        <h2 id="confirmed">Email address confirmed</h2>
+        <p>Email address <b>{{- .email -}}</b> is now confirmed!</p>
+        {{- if not .approved }}
+        <p>Once an admin has approved your sign-up, you will be able to log in and use your account.</p>
+        {{- end }}
+    </section>
+</main>
+{{- end }}