Google PubSub and BigQuery components miss dependency declarations

Google PubSub and Google Bigquery components require Apache HTTP client, which is NOT explicitly called out in dependencies.

As such they would work, if camel-http4 component is mentioned in the dependencies, but would fail on their own.

As a developer I would like to be able to define an absolute minimum of the dependencies, thus I need the component to import all components they rely on, themselves.