Allow ancestors to define a minimum license minting fee for all their descendants

[Spablob]

Problem

Monetization issue:

Currently, if descendants set the license minting fee to zero/nearly zero and monetize their IP by selling licenses at a high price (on ie. a marketplace) and those licenses are then used to link to new derivatives, then the ancestors will not receive any money upfront, despite the descendant IP having created links with new derivatives.

Suggested solution

To protect the ancestors' right to upfront monetization, each IPA owner could define a minimum license fee that will be enforced on all of its descendants. Any descendant can raise the said minimum license fee for its own descendants but is not allowed to reduce it.