docs: Update static docker docs to include inventory update script usage

[Haroon-Khel]

• commit message has one of the standard prefixes
• faq.md updated if appropriate
• other documentation is changed or added (if applicable)
• playbook changes run through VPC or QPC (if you have access)
• VPC/QPC not applicable for this PR
• for inventory.yml changes, bastillion/nagios/jenkins updated accordingly

ref #3415

Like the inventory.yml file, I recommend updating the DockerInventory.json via manual prs using the script (until I find a way to automate the automation 😄 )

[sxa]

It's a shame we need an API token to retrieve this information.