Feature request: Improve automation of source configuration

[ezzatron]

I have dotfiles repos for a couple of my workplaces, and it's pretty difficult to have each repo manage its own Grit config at the moment. I end up having to write a Grit config generator that pulls in and combines Grit config from multiple sources, which is extra hard in a Bash script because it's TOML and I can't just use jq.

So if I could do something like grit source set example 'git@github.example.org:{{slug}}.git', or alternatively have a config file like:

# ~/.config/grit/example.toml
[clone.sources]
example = "git@github.example.org:{{slug}}.git"

It would be a cool improvement I think.