Marcel Amirault authored 5 years ago and Evan Read committed 5 years ago

Updating redirected links in the development, install, policy
raketasks and university dirs. Should now link to final
URL to avoid redirect hops

The new version requires `python3` to be available. In omnibus
installation this is already a reality as we are currently pathing
previous `gitlab-markup` version to use `python3` instead of `python2`.

We are now requiring `python3` with the gem without having to patch it.

As a consequence to also make it easy to use it in development, we've
introduced a `Pipfile` and `Pipfile.lock`, working similarly to
`Gemfile` and `Gemfile.lock`, and added documentation on how to use
them.

This removes duplicated content from CONTRIBUTING.md and consolidate
everything under doc/development/contributing/.

This also fixes missing links.

Lastly, this moves the style guides from the "Implement design & UI
elements" page to a new "Style guides" page.

Signed-off-by: Rémy Coutable <remy@rymai.me>