* Adding grafana plugin version info

It was unclear if one can specify the plugin version to the environment variable. It is possible and works fine. Added it to the plugin information.

* Update typo docs/sources/installation/docker.md

* Applied all comments

Moved the information to make it more readable, fixed typos and added missing punctuation.

* Rewording and better example

More feedback, added example text. Did not manage to get newline for the example.

* added the missing space