Add --blueprint arg to timoni mod init cmd

[stefanprodan]

Add --blueprint arg to timoni mod init cmd to allow creating modules from custom blueprints hosted on container registries.

Example:

timoni mod init my-app --blueprint oci://ghcr.io/stefanprodan/timoni/blueprints/starter

The convention is for the blueprint modules to be named blueprint and Timoni will replace it with the init module name.

Ref: #251