Native Source for Facebook Ads

Feature request

Is your feature request related to a problem?

As a software developer working in technical marketing, it would be great UX to have an easy way to integrate Facebook Ads data into PostHog.

Describe the solution you'd like

There's an integration for Google Ads and something like this for Facebook Ads would be awesome!

Describe alternatives you've considered

My current approach is:

1. Using BigQuery's Facebook Ads Data Transfer Service to export the ads data into BigQuery.
2. Setting up BigQuery as a PostHog data source

The limitation with this approach is that backfilling isn't supported in BigQuery's Facebook Ads Data Transfer service. As specified in the limitations, only a maximum refresh window of 30 days is allowed. This means that data older than 30 days prior to the setup of the service can't be exported. My current workaround is to fetch the data from the API directly and then inserting the backfill into BigQuery, but this is a huge hassle.

Additional context

• I checked other issues like this one to verify that there are no issues regarding a Facebook Ads integration yet.
• The linked issue above references a question that touches up on the topic of a Facebook Ads integration, but it doesn't provide much detail.
• I'd be happy to help out with the implementation of this! Been using PostHog for a few weeks and I've been loving it so far🚀

Debug info

- [ ] PostHog Cloud, Debug information: [please copy/paste from https://us.posthog.com/settings/project-details#variables]
- [ ] PostHog Hobby self-hosted with `docker compose`, version/commit: [please provide]
- [ ] PostHog self-hosted with Kubernetes (deprecated, see [`Sunsetting Kubernetes support`](https://posthog.com/blog/sunsetting-helm-support-posthog)), version/commit: [please provide]

Start by reviewing the existing Google Ads source documentation and the BigQuery data-source documentation linked in the issue, then trace how a native source would obtain Facebook Ads data and support backfilling. Done means PostHog can integrate Facebook Ads data without the BigQuery workaround and can retrieve data older than the 30-day transfer window.