Validators repo migration

[p-ferreira]

• replace the penalty function (isabella, replaced the penalty function validators#147)
• stop vali from forwarding requests if dereg (pedro, inquinim, - Stop vali from forwarding requests if dereg validators#117)
• fix print_exception function call (pedro, fix print_exception function call validators#146)
• adds response return data (pedro, adds response return data validators#149)
• modifies status code to new synapse model
• sets default reward framework config
• ports and adapt unit tests from openvalidators repo
• brings run script to repo
• update readme docs

[Eugene-hu]

LGTM; nice job pedro!