Confirmation Emails of signup and password reset: content should be customized

The confirmation emails sent from Tribe for new account signup and password reset are controlled by the following two templates in `allauth`:
```
allauth/templates/account/email/password_reset_key_message.txt
allauth/templates/account/email/email_confirmation_message.txt
```

Some of the fields (such as `{{ site_name }}` and `{{ site_domain }}`) should be customized to replace the default such as `example.com`. Here is an example of email confirmation of new account signup:
```
From: tribe.greenelab@gmail.com
Subject: Tribe:Please Confirm Your E-mail Address
========================================
Hello from example.com!

You're receiving this e-mail because user xxx has given yours as an e-mail address to connect their account.

To confirm this is correct, go to http://tribe.greenelab.com/accounts/confirm-email/xyz.../

Thank you from example.com!
tribe.dartmouth.edu
```

Here is an example of email confirmation of password reset:
```
From: tribe.greenelab@gmail.com
Subject: Tribe:Password Reset E-mail
=======================================
Hello from example.com!

You're receiving this e-mail because you or someone else has requested a password for your user account.
It can be safely ignored if you did not request a password reset. Click the link below to reset your password.

http://tribe.greenelab.com/accounts/password/reset/key/blah.../

Thank you for using example.com!
tribe.dartmouth.edu
```

Obviously `example.com` (`{{ site_name }}`) and `tribe.dartmouth.edu` (`{{ site_domain }}`) in both emails should be customized.

Review allauth/templates/account/email/password_reset_key_message.txt and allauth/templates/account/email/email_confirmation_message.txt, focusing on the site_name and site_domain fields. Update the email content so it uses Tribe's customized values instead of example.com and confirm that both signup confirmation and password-reset messages show the intended site information.

Written by the indexing model from the issue text.