A refactor - idiomatic Go

[Southclaws]

I built this codebase back when I was quite inexperienced with idiomatic Go so there are some antipatterns and awkward idioms being used.

Since this is a project I encourage many beginners to contribute to, I think it's about time it's refactored to better reflect what real world production Go programs look like.

• Remove Extension interface
• Remove types package and put those types in the packages they are relevant to
• Maybe split up the storer interface
• Remove Action Provider interface for "Heartbeat" system
• Maybe just hard code things rather than try to abstract