Use OCI registry for deployments

[vdice]

Now that Spin uses OCI registries as its preferred mode of app distribution, installer scenarios should transition away from Bindle and use an OCI registry instead.

In the local installer scenario, the Docker registry container could be a good fit.

For the remote installers, the appropriate cloud provider offering could be utilized (perhaps with a fallback to the registry container launched as a Nomad service, if the cloud provider offering is either unavailable or not convenient to use).

However, beyond the infrastructure updates mentioned above, full support for an OCI-based deployment via spin platform deploy depends on the following two items as prerequisites:

• fermyon/platform-plugin#10
• deislabs/hippo#1653