* update local chain name in docker-compose and docu

the name of a local network changed from local to polkadot-local so
some local test environments were broken and the ticket #965 was
created

* using CLI flags --alice in local dev

as this directly adds the required keys to the keystore

Co-authored-by: Christian Seidemann <[email protected]>

* docs: Update Readme for PoC-3

* docs: Fix formatting and update Docker section

* docs: Fix formatting. Start trying to make consistent with Substrate repo

* docs: Move Two-Node example into Hack on Substrate