` scheme windows

I'm not sure of the ramifications here, because once a window is created it can be used - but not if the urlbar etc is missing, so we can probably detect that

https://github.com/mullvad/mullvad-browser/issues/202

tl;dr: bitwarden changed from using a new window (in reality in a new tab) to a using a small resized window anchored to the top right - for UX reasons - the problem is, RFP's new win will open it at 1400 x 900 max.

here's how it should look (I'm just using a blank page, it makes more sense on a login)

here's what actually happens

if you have the width, it actually positions top/left correctly, but the dimensions is the issue. I have just moved the second window for this image

Note: the scheme is moz-extension:// and the window has no tabstrip, urlbar, toolbar - so this means it's useless to repurpose for loading websites, so we should be good to exempt these cases from newwin dimensions

@ma1 cc @pierov