Add a library for AppManifest and operator deployments

[radiohead]

What

One thing that is missing from the SDK for ops purposes is a generic library that can be used for deploying app manifests and operators.

We should provide e.g. a generic Jsonnet library with helpers for creating operator deployments and uploading app manifests to the API.

Why

This will greatly reduce the amount of "day 2" friction, that arises when app developers start thinking about deploying their apps to remote environments.

This will also help with wiring all the defaults together (e.g. config parsing, setting up webhooks, exposing telemetry and so on).

In the future this library can also be used for housing default dashboards & alerts (i.e. the mixin) and to replace the current YAML-based local setup.