FIX - petascope should use rasdaman_user to query when authentication_type is empty

[Bang Pham Huu]

• allow_write_requests_from=127.0.0.1 in petascope.properties should be removed as it adds complexity unnecessarily (see below)

• authentication_type= (if set to empty) rasdaman_user=rasguest rasdaman_pass=rasguest rasdaman_admin_user=rasadmin rasdaman_admin_pass=rasadmin

Then, all requests without credentials → use rasguest. IF requests need admin permission (e.g. WCS-T), then one needs to add rasadmin:rasadmin as basic header authentication, e.g. wcst_import.sh -i ~/.rasadmin_credentials ingest.json