Bug 1096057 - Added cs-qwerty layout

The only difference from cs.js is that it is QWERTY, not QWERTZ.

Although, this is not an official layout according to the Czech
technical norms, it is very widely used “in the wild”.
Merge pull request #25998 from mcepl/cs_qwerty-layout

Bug 1096057 - Added cs-qwerty layout, r=timdream