Add "close friend" trust level for in-game relationship rank

[art-from-the-machine]

"trust" is used to tell an LLM how well a given NPC knows the player:

Mantella/src/conversation/context.py

Line 93 in d9973e3

def __get_trust(self, npc: Character) -> str:

When checking the length of Mantella conversations histories, there is a "close friend" level, but this level does not exist for the npc.relationship_rank check. This "close friend" level needs to be also added for npc.relationship_rank.