Remove GoogleBigQueryJDBC + dependencies from repository, add build instructions

[janblom]

Describe the bug
While the licenses of Google BigQuery and its dependencies allow using them within WhiteRabbit without restrictions, including them in the WR project, or packaging them as part of a release is not permitted. From the download site: "You can use these drivers without any additional license requirements, but cannot redistribute the drivers as part of an application." (retrieved at creation date of this issue).
The next (major) release of WhiteRabbit should not contain these dependencies. Instead, the source tree should contain a stub directory where anyone who wishes to use WhiteRabbit with Google BigQuery can download the dependencies from the site mentioned above, and compile WhiteRabbit for use with Google BigQuery. The stub directory should contain a README with instructions how to do this.

Additional context
See OHDSI WebAPI as an exanple of how to set this up.

[blootsvoets]

I haven't evaluated all of the dependent libraries, but I would gander that there's more database libraries WR uses that have similar don't distribute or personal use licenses...