Comment with plan and apply output collapsed

[cullenmcdermott]

Sometimes a terraform plan and apply can create a large amount of output. This can then clog up the PR comments and make it harder to follow the discussion. It would be nice if Atlantis commented with the plan/apply diff collapsed.

Here is an example:

Collapsed output:

This is hidden until expanded

[guitarrapc]

I love this idea!

[mechastorm]

I believe this is a similar to the same request in #126

[lkysow]

Yep this would be great and not too hard. It's the same request as #126 so I'll close this in favour of that.