Create 'testing' hosted instance in existing teams

### Description

There are a few ways to create a free Node-RED instance on FlowFuse, including a trial of FFC Pro and a download of OSS Flow-Fuse.

This task is to create a trial hosted instance for existing teams.

User story:
**As a user, I want to be able to create a temporary, free testing instance, so that I can try out a new instance before I am billed for it**

If users had a way to try out a new instance temporarily, this could encourage exploration with new instances, and lower the bar for designing better Node-RED architecture, as users would be more willing to spin up a temporary instance than one they would have to pay for immediately.

Proposal: allow each paying customer to create an instance in a new 'testing' mode. This would require the ability for the user to designate the instance as 'testing', and a way of limiting its duration (so that it doesn't simply amount to a free forever instance). Perhaps this could be done by limiting the total amount of time that a testing instance is running to three days per month.

### Epic/Story

_No response_

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate