Request: Try pricing page experiment w/ a third tier for "contact us" option

[Sampfluger88]

This request is expected to be doable in ≤1 sprint. It would be valuable even if nothing else ships.

It will be reviewed by the acting PM for the #g-website product group, and then hopefully prioritized, drafted, and implemented.

Goal

User story
As a enterprise buyer visiting the pricing page on fleetdm.com
I want to see a third tier of pricing that doesn't have a dollar figure attached
so that I can understand that enterprise pricing can vary based on number of host.

For help creating a user story, see "Writing a good user story" in the website handbook.

Changes

This issue's estimation includes completing the following:

• [ ] UI changes: TODO
• [ ] QA complete?

QA

The testing steps outlined below must be verified before the associated PR is merged. See "Quality" in the website handbook for help.

Manual testing steps

1. Step 1
2. Step 2
3. Step 3

In addition to the steps above, ensure changes have been checked at all breakpoints, and a browser compatibility test has been carried out on supported browsers.

Testing notes