Configurable application parameters

Server side changes for ketty#934 (closed)

• add permission for updateApplicationParameters mutation
• when populating application parameters on server start:
  • do not overwrite aiEnabled or terms and conditions
  • update integrations (add a new integration, or change Lulu's client id or authentiaction urls) without overwriting their disabled attribute
  • all other params (divisions, stages etc) are overwritten with the configuration file values
  • these changes apply only to instances of Ketty; other flavors (like Editoria) will overwrite application parameters on startup as they used to.