[Feature Request] Difftastic integration

[igorlfs]

Is your feature request related to a problem? Please describe.
Difftastic is a tool that uses treesitter to diff files based on their syntax. It'd be really nice to show diffs in Neogit using difftastic, instead of using nvim's diffopt.

Additional context
In the README there's a link to blog post about an integration with magit.