API-DOC enhancements: inventory with repository, task template typo in vault_id -> vault_key_id

[bernd-mueller-el]

During working with the API I found this two points:

• there is no example for type file with repository

{
  name:
  project_id:
  inventory:
  ssh_key_id:
  become_key_id:
  type: file
  repository_id:
}

• and there is a typo in creating task template, vault_id -> vault_key_id
  all is taken out of the database. Thanks