Add support for running a job in BQ

[ucom]

Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
Mage's internal BigQuery class only allows load() and export() but not to run a job in BQ without moving data from or to BQ.

Describe the solution you'd like
Add job creation to BigQuery class

Describe alternatives you've considered
Right now, as a workaround, it is possible to start an external BQ job by using a regular bigquery client (not Mage's internal one) but that does not allow to use Mage's with_config().

Additional context
Response from feature request in Slack channel