Upload config zip

1. ​POST https://opensolr.com/solr_manager/api/upload_zip_config_files
2. Note that if uploading a zip archive containing multiple files, you will use the upload_zip_config_files API endpoint 
3. Parameters:
   1. ​email - your opensolr registration email address
   2. api_key - your opensolr api_key
   3. core_name - the name of the core you wish to upload the schema.xml for
   4. userfile - your local config.zip file to POST and upload to the server

4. Example: https://opensolr.com/solr_manager/upload_config_files_form