Add rake tasks for creating analytics and usage databases.
Merge pull request #25 from heroku/bootstrapping-for-analytics-and-usage

Add rake tasks for creating analytics and usage databases.

These are necessary to get bootstrapping from a clean state working on vault-health. Two sets of tasks, one for usage, one for analytics. It shallow-clones the repos down just like the core and payments tasks, creates/drops databases, and runs the schema.