(prometheus) instant query support

these scenarios makes it easier debug panels based
on the same numbers without sharing datasource

ref #9332

introduce smtp config option for EHLO identity

Added --pluginUrl option to grafana-cli for local network plugin inst…

Update _navbar.scss

* replaced images, updating text(not finished)

* text uppdates for dashlist and singlestat(+img). updated the keyboard shortcuts

* deleted old shortcuts instruction

* another img update

with an alert rule that will always fire