Add ability to fetch probes for a product and all dependency components in a single request

[rafrombrc]

Currently fetching all probes relevant to a particular Glean product involves getting the top level probes for the product, then extracting the dependencies from the repositories json file and separately fetching the probes for each dependency. Since fetching all probes for a product, including dependencies, will be a common operation, it would be better for the probe info service to support returning all of these in a single request.