add: build-vm command to os subcommand

[xiro-codes]

Implements build-vm command into nh

[viperML]

Couldn't this be retrofitted into OsRebuildArgs::rebuild instead?

[xiro-codes]

Ill look into it, also love your blog it really helped me get into nix early on.

[viperML]

So what do you want to do with this command? It is named build-vm, but it actually runs the vm. Also it shouldn't install it into the system profile, and probably neither ask for confirmation or diff.

Edit: in hindsight perhaps it would be better to split it off OsRebuildArgs::rebuild

[xiro-codes]

I needed to test my config that was broken. so i added it didn't think much farther than that. but the unneeded sudo request is a problem ps. it was still broken but its fixed now

[xiro-codes]

Question how do I keep the tmp dir everything is created in so I can ask if they want to run vs just build the vm