Add email templates for user notifications and account management

- Created a base email template (base.html) for consistent styling across all emails.
- Added moderation approval email template (moderation_approved.html) to notify users of approved submissions.
- Added moderation rejection email template (moderation_rejected.html) to inform users of required changes for their submissions.
- Created password reset email template (password_reset.html) for users requesting to reset their passwords.
- Developed a welcome email template (welcome.html) to greet new users and provide account details and tips for using ThrillWiki.

django/staticfiles/admin/js/vendor/xregexp/LICENSE.txt

@@ -0,0 +1,21 @@
+The MIT License
+
+Copyright (c) 2007-2017 Steven Levithan <http://xregexp.com/>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.