Make --except flag work for individual functions and groups

Currently the `--except` flag only works for targets, unlike the `--only` flag which works for groups and individual functions as well. I know that a somewhat equivalent behavior can be achieved by grouping functions, but in our case there's a bunch of functions for which changing names is unfeasible, since they're used by multiple clients, so we don't want to put them in a group. Thus, currently there's no way to deploy every function which is not in a group other than specifying all of them individually with `--only`, so being able to do it with `--except` and groups would be ideal.