More custom autocommands

[TimUntersberger]

Add more custom autocommands similiar to #69.

A few events that come to my mind:

• NeogitCommit
• NeogitCommitAbort
• NeogitBeforeCommit
• ...

[RianFuro]

Maybe we could use the operations.lua-thingy to manage that centrally. I was planning to also hook that into a channel-structure (from here), so consumers from the lua side can be notified about changes. (if that's how it works, haven't looked into that too much)

[halfdan]

I would love to see NeogitPullComplete to automatically trigger recompilation of the project I'm working on.

[halfdan]

Pushed a PR to add that one event.

Unsure about using operations.lua - the file mentions it's but a stop-gap solution to deal with plenary shortcomings. Didn't want to build on top of something that was due to be replaced.

Maybe @TimUntersberger can advise here.