Raise matching priority of livery, especially for "related" a/c types

[TwinFan]

Current Situation / Problem
Let's assume we have:

• an live aircraft that is a B739 AUI
• any B739 model, like B739 DAL, but not a B739 AUI
• a B738_AUI CSL model

With the current matching, the B739_DAL model would be picked because of the exactly matching aircraft type. However, in this scenario, the B738_AUI would visually look better.

Suggested Solution
We need to raise importance of livery. But it cannot be raised fully above aircraft type, there must be a limit.

The limit should be related.txt. So the rule could probably be:

• Best match certainly stays matching aircraft type and livery
• Next should be "related" with matching livery
• Then matching a/c type, but non-matching livery
• Then "realated" with non-matching livery

Benefits
Looks better if "related" models with matching livery are available.

Additional context
First that based on this support thread.