The ResultSetToLineProtocol test class was not generating correct
line protocol for string output (appending `i`)
In addition, the PR improves the mock.NewResultSetFromSeriesGenerator
type with options. The one option added is `WithGeneratorMaxValues`,
to limit the total number of values produced by the SeriesGenerator.
* 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
Stuart Carnie
Jonathan A. Sternberg
Jacob Marble