Bringing more configuration settings from options.yml into /configuration. Renaming some. Please review, now is the best point in time to change the names of the configuration values.

...iguration api.

values in options.yml are still read and used. But they are not changable via
/configuration api and should be remove therefore.

This includes

 - anonymous ( was allow_anonymous )
 - registration ( was new_user_registration )
 - default_access_disabled ( was default_access_disabled )
 - allow_user_to_create_home_project ( was allow_user_to_create_home_project )
 - disallow_group_creation ( was disallow_group_creation_with_api )
 - change_password ( was change_passwd )
 - hide_private_options ( was hide_private_options )
 - gravatar ( was use_gravatar )
 - download_url ( was download_url )
 - ymp_url ( was ymp_url )
 - errbit_url ( was errbit_host )
 - bugzilla_url ( was bugzilla_host )
 - http_proxy ( was http_proxy )
 - theme ( was theme )