Add new system app to Flynn

new_system_app.md

Adding a new system app

For all system apps

• Add to bootstrap manifest template in bootstrap/manifest_template.json use deploy-app action unless app is pre-controller.
• Add to image to release manifest in util/release/version_template.json
• Add to updater SystemApps in updater/types/types.go

Additional steps for data appliances

• Add cli subcommands for console/backup/restore see cli/psql.go as an example
• Add provider to controller at boostrap time with the add-provider action in bootstrap/manifest_template.json
• Add backup for the appliance in the cluster backup tool in cli/cluster.go
• Add restore for the appliance for bootstrapping from backup host/cli/bootstrap.go