Plan and discuss how to fix keyboard shortcuts

[Rheeseyb]

This one isn't a simple bug fix, but rather a prompt for a discussion on how to fix / centralise keyboard shortcuts. Right now they are spread out throughout the code (some are checked as part of action handling, some are in event handlers, etc.) despite a lot of them being "global". The overall goals should be:

1. We can support user configuration of the shortcuts
2. We have a centralised place for adding and editing global shortcuts
3. Shortcuts that can't live in that centralised place are obvious to find (not just from the perspective of "where would this shortcut live", but also "what other shortcuts might exist somewhere?")
4. We can support different OSes (this should be a case of determining which of meta/cmd vs ctrl to use based on a library that determines which OS the user is using)

[maltenuhn]

My take

1. We should build this in a way that makes it the easiest for us to experiment quickly.
2. We should assume that user configurability is an inevitability

Personally, I really like the approach Monaco / VSCode took with keybindings in a JSON file: https://code.visualstudio.com/docs/getstarted/keybindings#:~:text=All%20keyboard%20shortcuts%20in%20VS,This%20will%20open%20your%20keybindings.

[alecmolloy]

#231 is dependent on point №2 being fixed here

[seanparsons]

The following tickets have been created:
#272
#273
#274
#275