Add a crontab that runs the data pipeline daily

Summary:
So each day starting 10 pm PST, we scrape vim.org plugins, then
github.com/vim-scripts plugins, then recently-updated dotfiles github repos,
then we aggregate all known GitHub plugin repos, then we scrape 3600
non-vim-scripts plugin GitHub repos plugin repos.

Test Plan: Each command was run on the server and the output of ~/logs/cron/*.log examined.

Reviewers: xymostech, spicyj

Reviewed By: spicyj

Differential Revision: http://phabricator.benalpert.com/D210