Make it possible to invoke template lock in the UI

[jameskoster]

With #43037 merged, we need to add a way to invoke this condition in the UI.

In the PR it was hypothesised that the following lock configuration on a container could act as the trigger:

But this is just one idea, there are doubtless others to explore.

[karmatosed]

I want to switch labels to feedback for now. This doesn't discourage any input but it's been a while and I suspect this might be an easier way to get engagement (or hope) for now.

What ideally we are looking for in this is:

• Is the proposal still valid?
• Are there other options to implement this?