Create scaffold config in cwd instead of scaffold repo directory

[benjaminbojko]

Currently the user.ps1 config is created in launchpad-scaffold/config.

This makes the config hard to find and port over. I think the default should be to create it at the cwd from where a user runs launchpad, and provide the option to pass in a path to the scaffold config (via CLI and via the main launchpad config object/file).

The config should also be renamed to something more meaningful, like launchpad.scaffold.config.ps1.

The config itself is currently auto-generated by copying launchpad-scaffold/config/default.ps1.