assetstools backend: include base monobehaviour fields

[jakobhellermann]

The AssetStudio backend includes the monobehaviour base fields in the generated types, but the AssetsTools backend doesn't.
This PR adds them to AssetsTools, but hardcoded. Maybe it should use the tpk class database, I'm not sure.

The alternatives would be to

• never include monobehaviour base fields (dependencies like UnityPy would have to change their reading code)
• make it configurable

I don't have a strong opinion on the matter, as long as it's consistent.

[jakobhellermann]

Also, should assembly names contain .dll or not? it would be nice to be consistent on that

EDIT: I think the part that's inconsistent is actually unity, on one game m_Script.m_AssemblyName contains .dll and on another it doesn't.