Fix article sharing

[WillieCubed]

Fixes #917, #930, #985 by using a proper share picker.

[pretzelwagon]

Does this fix work? Why hasn't it been merged? Such a painful bug, as I use sharing all the time; causing me to consider leaving to another reader.

[tamsky]

test failures simply need to be updated to change the expected result to follow this change...

    java.lang.AssertionError: Expected action <android.intent.action.SEND> but was
<android.intent.action.CHOOSER>.

[hidroh]

Hey all sorry for late reply, let me review this. I think I have been going back and forth on this chooser vs non chooser a few times. If I remember correctly the chooser doesn't offer the options Just once/Always, and people complain about that, while non-chooser (relying on platform chooser) has different behavior on Samsung devices.

[garymoon]

Thank you so much for this @WillieCubed! I recently had need to make an adjustment to another OSS app I use, and thought I'd try to tackle the share menu in Materialistic while I was at it (it's the only app I use with the old-style share menu so I miss out on direct share and pinned apps). Thanks to you the process took me 10 minutes from start to finish.

@hidroh Thank you of course for Materialistic! If you want to consider merging this PR I'm happy to help with testing or whatever else a non-android-dev might be useful for. I have access to a OnePlus 3t running Lineage and a OnePlus 5 running stock Oxygen.

Thanks again guys!

[WillieCubed]

Bump for @hidroh