(extensions.decompile) Standardising decompile extraction & processing

[snake-biscuits]

Decompiles should create a generic editor.MapFile
Can convert to a specific map format later for saving

Will require some standardised way of copying data between different types of MapFile

Dependencies

• (extensions.editor) MetaPattern string conversion is an ugly mess #164
• (extensions.editor) .save_as(filename: str) method for all MapFile classes #163
• Move extensions.editor.generic into utils.editor #169