Method Intermediary Mapper

[jamierocks]

Will be based on https://github.com/CadixDev/Survey/blob/e837b20544b52b1a7bdadb28b0538b02fc12663f/survey/src/main/java/me/jamiemansfield/survey/mapper/IntermediaryMapper.java.

Likely to be implemented in 2 (or possibly more) passes again.

• Needs to handle generics better, going off the signature rather than descriptor.
• Needs to handle Broken parent SRG mappings ModCoderPack/MCPBot-Issues#646