c9375cac5e
Descriptions were updated in attempt to make it more clear for readers,
re-phrasing and linking missing docs.
`eval_delay` was added to tests to verify it can be unmarshalled.
`eval_delay` is now applied before timestamp alignment to make it more predictable.
Before, if delay < interval the timestamp won't be aligned.
`eval_delay` and `eval_offset` was added to API output.
`PreviouslySentSeriesToRW` converted to private `previouslySentSeriesToRW`.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
