Copy query button

Created by: attfarhan

Feature request description

Add a button in the search bar to copy the entire query. It's not currently possible to copy the entire raw query easily, since patternType and case filters are removed and put into toggles. We should add an easy way to do so.

Context: https://sourcegraph.slack.com/archives/C0W2E592M/p1582646381006600

Also needs to solve the problem for interactive mode, where filters are in separate inputs.

See https://docs.google.com/document/d/1AtaJ8XvhDskcZOQtynuLKYq8thd727nI7baWNGGuEkU/edit?disco=AAAAGdpygKY for Garo's feedback on this.