Enhancement(Esc key hide modal)

[shakti97]

I have verified that this pull request:

• has no linting errors (npm run lint)
• is from a uniquely-named feature branch and has been rebased on top of the latest master. (If I was asked to make more changes, I have made sure to rebase onto master then too)
• is descriptively named and links to an issue number, i.e. Fixes #123

Fixes #1312

I have 2 solution for this enhancement,

1. add keylistener in every component (File/Folder) and then trigger close modal from those component
2. add global listener for ESC key and close modal from there

I have taken the 2nd approach, as the first looks to add redundant code in all component.
@catarak have a look and suggest changes if any :)

[catarak]

Thank you!! Looks good to me. I think this is the right approach.

I think that this state (whether or not these overlays are visible) should be moved from Redux to React, and then it would make sense to put the keyboard handler in the component, but for now, this is okay.