[Heroku Connect]: Filter which rows sync

### Required Terms

- [X] I agree to follow this project's [Code of Conduct](https://github.com/heroku/roadmap/blob/main/CODE_OF_CONDUCT.md)
- [X] I have read and accept the [Salesforce Program Agreement](https://www.salesforce.com/company/program-agreement/)

### What service(s) is this request for?

Connect

### Tell us about what you're trying to solve. What challenges are you facing?

In a Salesforce Org with large data volumes, the price of using Heroku connect can get high very quickly, enough to be prohibitively expensive for many potentially reasonable use-cases. When you overlay volume based pricing for both sync and postgres storage, with the lack of sync filtering, I have no mechanism to control my Heroku Connect costs as my org grows organically, and even worse, I end up paying to sync and store data that provides me no value. In many cases, the lack of filtered sync decreases the value I get from syncing the rows I want to sync, because of the extra effort and performance impact that comes from sifting through the extra data.