rb-site: Deploy correct Apache 2.4 authorization

Apache 2.4 uses a different authorization config than 2.2. This change adds
some smarts to rb-site to detect when using Apache 2.4 and use "Require all
granted" instead of "Allow from all".

Testing Done:
Applied the patch and deployed it on a system with Apache 2.4.2. It properly
detected the version and put "Require all granted" into the apache-wsgi.conf

Bugs closed: 3210

Reviewed at https://reviews.reviewboard.org/r/5338/
Add render_value to various PasswordInput fields.

For password inputs that are part of settings (LDAP auth, mail host, and
repository), the password wasn't pre-populated into the form, which meant that
if you changed said settings, you'd need to re-enter the password. This is
highly annoying. I've added `render_value=True` to the affected PasswordInput
ctors.

Testing done: Checked that saving a password was "sticky".

Fixes bugs 3037, 3167.