Improving readline bindings

[binamkayastha]

There was an issue reported a while back: #398
It seems to be rejected, but some of them have been implemented like alt-d, so I not sure when it was updated.
Either way, ctrl-u still doesn't work, and ctrl-d should exit the terminal if there are no characters to delete. I would like to work on potentially fixing this, but I have no idea where the keybindings are for the readline bindings. I can find other bindings, but couldn't find (for example) alt-d at all.

[ABouzo]

I believe that all shortcuts that manipulate the input are in the PromptComponent.tsx

[ABouzo]

I was think we could create an external JSON that could be edited to change some preferences. Similar to how VSCode does it right now.