site_code is not available in configuration

[maurerle]

As far as I know, yanic and ext-respondd distinct between a site_code and a domain_code.
This is important if yanic is configured with:

# append on the site_code the domain_code with a '.' in this output
# e.g. site_code='ffhb',domain_code='city' => site_code='ffhb.city', domain_code=''
#domain_append_site = true

otherwise the domain ist something like .dom1

I would suggest to add such a setting so that one can add a site config in respondd.conf