[feature request] dolt stash apply

[DavidLokison]

Would be awesome to have this functionality to work on parts of the stash... I have a tendency to have unimaginably large dirty workspaces and need to break some things apart for commits. Also might be helpful for separating schema and content updates in tables.

[fulghum]

Thanks for the feature request David! stash apply is pretty handy with Git, so makes sense that it'd be useful for Dolt, too.

This one seems like it should be pretty easy – we'd just need to invoke the logic to apply a stash, without popping it off the stash stack. I'll check with @elianddb and see if he's able to pick this up next week.