Provide symbols for our new accessible doors for use in text

[Miepee]

Around 6AAFAC there are a lot of placeholder/empty graphics we can probably replace
If not those, then we could very likely replace the unused L+R sprites.

[biosp4rk]

Do we want the graphic changes to be part of the asm repo? For the patcher we just need to add a few entries in char_map_mf.json

[Miepee]

Yeah. Would be a bit weird to ship the graphics only within the patcher