Merge branch 'stable-sync/2.1.0' into 'develop'

Merge stable in develop and bump development version

Closes #1610, #1621, #1613, #1375, #1374, #1614, #1422, #1595, #1620, #1364, #1640, #1643, #1653, #1624, #764, #1687, #1698, #1670, #1677, #1727, #1559, #1746, #1313, #1810, #751, and #866

See merge request pleroma/pleroma!2928