Show Target Environment availability when approving a request

# What is currently missing?

Currently when approving a request that request could fail, if it fails the request stays in the approval section without any additional information on why it failed.

# How could this be improved?

By adding a traffic light icon on the target environments availability we can show the approver if the environment is available or not.
This could also be used to prevent approvers from submitting the request until the environment is available again.

# Is this a feature you would work on yourself?

* [x] I plan to open a pull request for this feature