* Add documentation for Exemplars

* Update prometheus.md

Add note + provisioning info

* Update docs/sources/datasources/prometheus.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update prometheus.md

* Update prometheus.md

Add exemplars options to the settings table

* Update docs/sources/datasources/prometheus.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update docs/sources/datasources/prometheus.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update prometheus.md

Add more content to exemplars

* Update whats-new-in-v7-4.md

Add link to exemplars

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>