The detailed plan for this is laid out in
https://github.com/prometheus/prometheus/issues/16572 .
This commit adds a global and local scrape config option
`scrape_native_histograms`, which has to be set to true to ingest
native histograms.
To ease the transition, the feature flag is changed to simply set the
default of `scrape_native_histograms` to true.
Further implications:
- The default scrape protocols now depend on the
`scrape_native_histograms` setting.
- Everywhere else, histograms are now "on by default".
Documentation beyond the one for the feature flag and the scrape
config are deliberately left out. See
https://github.com/prometheus/prometheus/pull/17232 for that.
Signed-off-by: beorn7 <beorn@grafana.com>