Lower the Android version requirement

[Lost-Entrepreneur439]

Is there an existing request for this?

• I have searched the existing issues

Feature description

Right now Molly's minimum requirement is Oreo, which seems unnecessarily high. Devices which run Nougat are still somewhat common where I am (such as the Samsung Galaxy S6 and BlackBerry Motion), and I've looked through the source code, and I don't see any differences that changes the compatibility from Signal's minimum version (which is Lollipop). Unless there is actually something preventing it from working on Lollipop, Marshmallow and/or Nougat, the minimum should be lowered back to Signal's minimum of Lollipop.