WIP:Remove internal api (same as PR 237)

This was already +1ed, but reverted.

https://github.com/rackerlabs/blueflood/pull/237

This means we will use TenantTTLProvider in all the places.

Set things up by:
* fixing a few bugs in RollupType
* expose RollupType in Rollup

Then:
* use the already implemented providers
* get rid of TtlCache, InternalAPI, Account, etc.