Add new global application settings for default project and snippet
visibility levels.

By imposing this rule we avoid having to demand that 'ldapmain' exists
in the settings initializer.

Closes #1305

successful Git over HTTP authentication.

Add logging when a ban goes into effect for debugging.

Issue #1171

Add checkboxes to the application settings page for restricted
visibility levels, and remove those settings from gitlab.yml.

for his work and help)

Remove markdown syntax from config file

On some misconfigured GitLab servers, if you look in production.log it looks
like all requests come from 127.0.0.1. To avoid unwanted banning we
white-list 127.0.0.1 with this commit.

This reverts commit 533f4cdf.

Before this it would fail because git hooks automatically prepend
things to the path, which can lead the wrong Ruby version to be called
in which dependencies are not installed.

To make sure that this is correct, the forked_merge_requests commented
out test that depends on this change was uncommented.

For that test to pass, it is also necessary to setup the mock server
on port 3001 under test_env.rb.

And add some advertisement to use GitLab EE