* refactor(storage): move type ByTagKey to the only package that uses it
* refactor(tsdb): use types in tsdb/cursors
* refactor(tsdb): remove unused type SeriesIDElems
* refactor(tsdb): inline only use of tsdb.ReadAllSeriesIDIterator
* refactor(tsdb): move series file to its own package
* refactor(storage): remove platform->influxdb aliases
* fix(storage): simplify storage/seriesCursor
storage/seriesCursor releases series file and TSI references sooner.
Remove unhelpful request object, inherited from 1.x
* chore(storage): replace SeriesCursor interface with sole implementation
Jonathan A. Sternberg
Jacob Marble
Stuart Carnie