feat(data-warehouse): Add a billable field to jobs

[Gilbert09]

Problem

• To prep for the V2 pipeline release, we need a better way to distinguish which jobs the customer should be billed for and what jobs should appear in the posthog UI

Changes

• Added a billable boolean field to the jobs model
  • Defaults to true
• Added a migration to set all jobs as billable except for the V2 jobs
• When we release the pipeline, we just set the V2 jobs as billable and V1 jobs as not billable, no other changes needed in terms of billing and jobs in the UI

Does this work well for both Cloud and self-hosted?

Yes

How did you test this code?

Updates tests