[#62896842] Contacts file Importer

Missing method: get_schoold_id

Rollback is not defined also
[#62896842] Proccess Contacts files

Creation of ContactsFileImporter
[#62896842] Config files related to kshema

API_KEY and HOST (the api_key is going to be updated)
[#62896842] update realtime_status to allow retry and remove school_id param
[#62896842] Changes in kshema api

new url and params
[#62896842] failed_files controller

1) get failed_contacts_ids
2) start new update
3) change status_url
[#62896842] View: Retry contacts files uploads