Add back multi-sig support and fix the multi-sig check for harmony nodes#3337

Merged

rlan35 merged 2 commits intoharmony-one:mainfrom rlan35:main

Sep 10, 2020

+765-415

Commits on Sep 10, 2020

Revert "Revert "Add multi-sig merged messaging logic (harmony-one#3300 )""
rlan35
committed
Allow harmony nodes to sign multisig from multiple accounts
rlan35
committed