[WIP] Add block justification support#309

Draft

jakehemmerle wants to merge 2 commits intoparitytech:masterfrom

jakehemmerle:justifications

Commits on Jun 29, 2021

justification draft 1
jakehemmerle
committed

Commits on Jun 30, 2021

fix capitalization in migration

jakehemmerle
and
insipx
committed