Update the "managed_license" resource to follow the new conventions necessary for 15.0

Created by: PatrickRice-KSC

Feature Description

Per the managed license API documentation, the current approval and blacklisted verbiage is now deprecated and will be removed in 15.0 in favor of allowed and denied.

This issue will update the allowed values in the terraform provider to accept these values in addition to the current approval and blacklisted values, and we'll likely want to open a second PR in may that removes the existing values.

Do you want to implement this?

• I would like to implement this myself 👷