Support multiple registry query on devfile registry library

[elsony]

The current registry library code support query of the list of devfiles in a given registry. This feature expands the existing function to support queries on multiple registries.

This item includes:

1. Update existing registry listing API to accept a list of registries when querying the list of devfiles in a registry.
2. Update the return data on the registry query to include the registry information on each returned devfile entry.

Note: this feature is only applicable to the go library. This feature will not cover the REST API since the client that uses the REST API is talking directly to a specific registry.