On import process interruption `vmctl` now prints the max and min timestamps of:
* last failed batch if import ended with error;
* last sent batch if import was cancelled by user.
To get more details for each timeseries in batch user needs to specify `--verbose` flag.
The change does not relate to `vm-native` mode, since `vmctl` has no control over
transferred data in this mode.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1236
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* add more documentation on OpenTSDB migration explaining what chunking means
* more clarification of OpenTSDB aggregations
* break out what a retention string becomes
* add more docs around retention strings
* add example of running program and fix mistake in how hard offsets are handled
* fix formatting