[Feature] Warn before closing Environment Configuration

[edbrannin]

Steps to reproduce:

1. Click on Environment selector
2. Click Configure
3. (Create an Environment if none exists yet)
4. Add a row to the Environment table, then type in it
5. One of:
   • Press the 'X' in the upper-right
   • Click anywhere outside the modal

Expected result:

One of:

• The modal prompts before closing (like closing a Request with changes)
• The modal auto-saves (I think this is the worse option)

Observed Result

The modal immediately closes. My changes are not saved.

Notes

As @martinsefcik suggested in #1040, the easiest way to resolve this issue (and that one) might be to make Environments a tab, like Variables, Runner, & Collection [Settings].

[hrehovam]

@sanjai0py Hi, I am student of Technical University of Košice, Slovakia. One of our subjects is about resolving open source issues and I would like to work on this one. Can I work on this feature?