This commit carries out the initial refactor of the tsi1.Index into
tsi1.Partition. We then create a new tsi1.Index that will be an
abstraction over a collection of Partitions.
This commit adds a basic TSI versioning scheme, by adding a Version field
to an index's MANIFEST file.
Existing TSI indexes will not have this field present in their MANIFEST
files, and thus will be deemed incomatible with the current version.
Users with existing TSI indexes will be able to remove them, and convert the
resulting inmem indexes to the current version of a TSI index using the
influx_inspect tooling.
Edd Robinson
Ben Johnson
Stuart Carnie
Jason Wilder