Code for guest routes moved to their own folder so that we don't need
multiple api calls.
Serializer class for roles has been simplified with methods for
validation of each field and a separate one used in invites without
requiring the person field.

Resolves: GREG-61

Allows search using e-mail and mobile phone, limiting results to 10
first matches

To make handling info about roles and persons easier we split them into
separate objects. The Profile page has now gotten its own api endpoint
where a sponsor has access to all guests instead of only those they are
sponsor for which is used on the sponsor frontpage. This is necessary
since a sponsor may want to give a role to someone they are not
currently sponsor for.