supported / target browsers for helix pages

[davidnuescheler]

looking at current browser marketshare on: http://gs.statcounter.com/browser-market-share/

i think that we should support the top 3 browsers for desktop and mobile,

...as of May 2019:

Desktop

• Chrome - 69.09%
• Firefox - 10.01%
• Safari - 7.25%

Mobile

• Chrome - 59.43%
• Safari - 20.81%
• Samsung Internet - 7.12%

i don't know that we would need to be very specific about the versions of these...

i am definitely open to supporting more browsers if we want to, but initially i don't think we need to make the list much bigger.

[rofe]

i don't know that we would need to be very specific about the versions of these...

I don't think so. These are all evergreen browsers, so we always support the latest version.

[kptdobe]

This should be tackled as part of #8 and documented in adobe/helix-home.