Create or update an entitlement rule for an offering, and optionally select one of its offer options. Rules are scoped to one of three levels and the scope is chosen by how much of the hierarchy is identified: pass company_account_id and user_uuid as * for a reseller-level rule that applies to every user of every company, pass a company with user_uuid as * for a company-level rule, or pass both a company and a user for a user-level rule. A more specific rule overrides a broader one when entitlements are resolved. All three scope fields must be sent. The rule is always created under the authenticated reseller account. The company must belong to the authenticated reseller account and the user must belong to that company.