Change repo_names to forge module repos

Prior to this commit, the rake tasks `job:import and
`job:import_if_sunday` only looked at the puppetlabs repositories
`puppet`, `hiera`, `puppetlabs-stdlib`, and `facter`. This commit makes
it look at a (dynamically generated) list of repositories for puppetlabs
forge modules.
Add regex check for getting repo_names
Add regex check for getting repo_names - for real this time
Add repositories table to database

This commit adds a repositories table to the database, and has the
pull_requests table get repo info through there. This commit also adds a
rake task that updates the repositories table from the forge api.
Reorganize layout

Prior to this commit, the website was designed in order to only view
pull requests for 4 repositories. If you wanted to display many more
than that, then the "# of requests per repo" graph did not display
nicely.

This commit reorganizes the layout, removing the "# of requests per
repo" graph entirely (until I can find a better way to include it), and
providing a sidebar that lets you filter data for individual pages.