community/grafana*: upgrade to 9.4.7

Switched grafana-cli and grafana-server wrapper to shell - official ones search for grafana in $PATH, mine - hardcode absolute path. Not sure what behavior is better.

I could also completely remove them, possibly causing breakage for some users with modified init.d, but grafana docs often mention those binaries so I decided to keep them.

Also removed text mentioning grafana-image-rendering since it's still in testing, has some minor bugs (like process not fully stopping) and grafana documents manual installation in their official docs.