Feature to make BrowserPicker default browser in windows

[mortenn]

WIth the announcement that Firefox has worked around Microsofts hijinks, it would be good if BrowserPicker could do the same.

I think this is the relevant bug on mozilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1703578 And this the relevant source file: https://github.com/mozilla/gecko-dev/blob/master/toolkit/mozapps/defaultagent/SetDefaultBrowser.cpp

[mortenn]

Microsoft broke Mozillas hack, this isn't feasible at this time.