Require commit messages

[darkmuggle]

Since joining the Chia community something that has both bothered me and frustrated me, is the lack of commit messages. When looking at a patch or change, I've had to read the code to get a sense of what been changed. But more importantly, the rationale for the change is missing -- I have to guess about the change.

As a user, I would appreciate commit messages.
As someone who wants to contribute, commit messages are immensely helpful.