This change deprecates the
`querier.shuffle-sharding-ingesters-lookback-period` option, instead
setting the lookback period from the value of the
`querier.query-ingesters-within` option. Outside of our own integration
tests, there's no situation where it's useful to set the lookback period
to a different value than the `query-ingesters-within` option.

This also adds a new option `querier.shuffle-sharding-ingesters-enabled`
that can be used to enable or disable shuffle sharding on ingesters on
the read path instead of using the lookback period for this.

Fixes #1810

Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>

Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>

Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>