Use registry.odigos.io for images and update default image-prefix

[damemi]

This updates the code to use registry.odigos.io/* instead of dockerhub/keyval/. This also changes the default for the image-prefix setting to registry.odigos.io

The reasoning for this is that previously, all of our images were on dockerhub under the keyval org. For example: keyval/odigos-odiglet

This really evaluates to docker.io/keyval/odigos-odiglet, meaning that even though the default value for --image-prefix is technically empty, it is actually essentially defaulting to --image-prefix=docker.io. This is why the new default --image-prefix is changing.

In addition, with the new registry, all of our images are hosted directly under the main domain, such as registry.odigos.io/odigos-odiglet

So, there is no need for us to add the keyval/ prefix to our images anymore. Similarly, there is no reason for users to add keyval/ to their own images when using their own registry. This is why we are dropping it from the default image names.

These changes may be initially breaking to some users, but I think it is a lot more intuitive:

• Default prefix: docker.io->registry.odigos.io
• Default image names keyval/odigos-<component> -> odigos-<component>