set response headers from actions

### Is your proposal related to a problem?
i like to set an authorization header in my signup action function on the server to respond a session token

### Describe the solution you'd like
1. make it possible to transform a session token, returned by the payload to a header value
2. set the response header in the api function which is called by an action

### Describe alternatives you've considered
- returning the token via the payload
- returning the token via a cookie

i wasn't able to find something about setting headers from actions in the docs.
maybe my approach doesn't make sense at all and i need to consider doing it with another approach?
every hint is welcome.