Add action to dismiss search bar

[diegogangl]

Pressing ESC now closes the search bar again. Good times

fixes #1003

[nekohayo]

A quickie glance at the diff tells me that the Ctrl+F key would still clear the search instead of refocusing; would you want to address #952 at the same time in this MR in the same commit, or better to keep it separate?

[diegogangl]

Best to keep the PRs short and sweet for now