Royalties

[zajck]

Added flexible royalty specification to the protocol.

When seller is created, a default royalty recipient (trasury) is created. Admin can then add more royalty recipients to the allow list.
Admin at the same time also set minimal royalty that recipient should receive.
When assistant creates an offer they choose a subset of royalty recipients (can be empty) and sets individual royalty percentages, which should be at least as the minimum, set by the admin.

Changes:

• Added royalties related revert reasons
• Added new structs RoyaltyRecipient and RoyaltyInfo. RoyaltyInfo format is directly compatibile with royalty registry. RoyaltyInfo was added to existing Offer struct.
• added RoyaltyRecipientsChanged event
• added new methods addRoyaltyRecipients, updateRoyaltyRecipients, removeRoyaltyRecipients and getRoyaltyRecipients
• updated updateSeller to update default royalty recipient if treasury is changed
• refactored part of the code that was duplicated across updateSeller and new methods. I added two internal functions isCallerAuthorizedCheck and validateAdminStatus
• changed createOfferInternal to handle RoyaltyInfo
• changed createSellerInternal to create a default recipient
• added royaltyRecipientsBySeller and royaltyRecipientIndexBySellerAndRecipient mappings to protocol lookups
• added domain scripts and tests for RoyaltyRecipient and RoyaltyInfo.
• updated domain scripts and tests for Offer
• added/updated unit tests

Other changes:

• fix percentage typo: close RoyaltyPecentage typo #594

TODO:

• update domain model diagram
• integration tests with royaltyRegistry

[coveralls]

coverage: 98.609% (-0.02%) from 98.627%
when pulling 5c4cb54 on royalties-2
into f685df3 on main.