Set up InfluxDB on the monitor nodes

This MR adds InfluxDB on the monitor nodes to store GPT test results.

Issue: gitlab-org/quality/performance#205 (closed)

Room for improvements:

• Move docker install to a separate role and update it in all places where docker is installed:
  • FYI from Grant(will be done in another MR): https://gitlab.com/gitlab-org/quality/performance-environment-builder/-/merge_requests/18#note_323614322
• Make a new variable for {{ external_url| regex_replace("\\/$", "") }}
  • Done in this MR