Multiple --status arguments to `rebuildctl pkgs ls` should be possible

[kpcyrd]

This call is currently invalid, but wouldn't need to:

rebuildctl pkgs ls --status GOOD --status BAD

To support this, the api needs to accept a request like this as valid however:

curl -v 'http://127.0.0.1:8082/api/v0/pkgs/list?status=GOOD&status=BAD'

Or this (without breaking backwards compatibility):

curl -v 'http://127.0.0.1:8082/api/v0/pkgs/list?status[]=GOOD&status[]=BAD'