CIP1: Replace multisig in the config contract with a threshold signature

[chefsale]

Currently every blockchain integration has a multisig managing the config contract.

This leads to several things:

• Adding new chains is slower then it should be as we have to rewrite the multisig for every single VM having a threshold signature would mean we just need to implement a verify method instead
• Having to reimplement the multisig implementation also allows for more bugs and vulnerabilities plus increases cost of audit, having a unified implementation mitigates this a lot.
• All the votes are currently public and visible, but with the replacement we would make just the end result public instead.
• The only question which is tricky is the addition and removal of members which is currently pretty straight-forward, but we would have to have some refresh calculation on the protocol level when people are added or removed.

This is something we have to implement in the future, but not critical at the moment. cc: @xilosada @alenmestrov @miraclx

[chefsale]

Also, this should become an improvement proposal and potentially a bounty.