add method to consistently convert a name string to a login name
convert user login names to downcased no underscore strings
leave user login field as is and clean the OwnerName#name field instead

remove spaces and downcase the OwnerName name field for use in URL filtering.
store the group name as typed to the display name if it hasn't been set
use consistent class method definitions
add owner_name attribute to User & UserGroup serializers

expose the linked owner_name#name attribute on each model representation for use in filtering, e.g. projects index.