R1:a741f5d65c10

Change some instances of "phabricator" to "phorge"

Summary:
Just a small set of replacements in locations that seem innocuous (user-facing messages, documentation, etc.)

Ref T15006

Test Plan:
Nothing should change in terms of behavior. The places where these changes were made should now say "phorge".

Example tests:

- Manage a single User and click on Delete User and see the popup
- Run a test email and check the output
./bin/mail send-test --to username
- Visit /maniphest/, shift+click on at least 1…