Cleaned up and rearranged code for bootstrapping. Made use of kv.LocalDB in BootstrapCluster. Now making sure to allocate from node id allocator (so it's value is properly initialized to 1) and for store id allocator (also so it's value is...

Summary:
...initialized to 1). Moved code to initialize the first range's address metadata to kv/db.go.

Added datacenter to storage/config.go:Replica as it will be necessary
when choosing the best replica to read from based on client location.

Added setup code for pulling datacenter, pdu and rack values either
from command line flags or environment variables.

Test Plan: go test

Reviewers: andybons

Reviewed By: andybons

Subscribers: levonlloyd

Differential Revision: http://phabricator.andybons.com/D38