Quorum Upgrade Policy

[dariorussi]

Implementation of a k out of n policy for package upgrade (quorum upgrade policy). This is the simple solutions we talked about and we plan to go out with. Docs/tests should be decent enough for an understanding but much more is coming. What this does is along the following lines:

• An owner of an UpgradeCap can wrap it into this policy which will allow for given "entities" to vote on upgrades.
• Registered addresses get a VotingCap which is used to vote for proposed upgrades.
• The signer performing the upgrade must be the same as the proposer of the upgrade
• Multiple upgrade can be up at the same time and first committed wins (as expected)

[dariorussi]

comments and feedback on the original PR have been addressed. There is more coming in terms of docs, script and testing