Add feature to let us kill a deploymnet

[matthewstick]

From the admin panel, we have to wait and watch a pending or active deployment. Sometimes they also get stuck and we have to email. It would be good to allow us to kill it, assuming its safe to do so during much of the process - and then when it is no longer safe to kill it then block us from killing it to not break anything accidentally. Thanks!

[jamesmacwhite]

I had a similar request: #90

But for a different reason. Mainly a last chance if you realise you've pushed something that's about to bring the house down.

[matthewstick]

@jamesmacwhite Thank you - I tried searching but didn't see your note. Yeah same here - I was concerned about a deploy running about to bring house down. Luckily it didn't, but that's where i realized how often I wished I had this feature.

[jamesmacwhite]

Yup, I had that exact situation once and could only watch as the inevitable happened. Back when I posted the original request, deployment times were much longer, but they have improved, so a quick hotfix onto main is more easily recoverable now, back then deployment times were anywhere up to 20 mins, which wasn't ideal for such a situation where you need to get a fix up ASAP.