grafana.log location and other improvements in pmm-info.sh

[riveraja]

There must have been changes to the location of the grafana.log files in docker deployments

==================== Extended info: cat /var/log/grafana.log inside docker container:
  cat: /var/log/grafana.log: No such file or directory

Proposed fix:
https://gist.github.com/riveraja/96b03469bcf0891b3a404baa9619767e#file-gistfile1-txt-L48

Also propose to add support to collect data from PMM for Virtualbox/VMware deployments.
https://gist.github.com/riveraja/96b03469bcf0891b3a404baa9619767e

[RoelVdP]

@riveraja thanks for the input. Would you like to propose a patch/PR?