Accounting: Collect W-9s for payments

[garyhtou]

This ticket is a result of conversations around payment compliance.

We need to collect a W-9 or W-8 BEN for all payments (excluding reimbursements) regardless of the amount.

Requirements

• Legally, the W-9 requirement is $600+, but we will be requiring it for all payments.
• We need an updated W-9 per entity per year
• We will collect a W-9 regardless if it's a payment to a contractor vs cooperation.
• Ideally, a user should not need to re-upload a W-9 if we have an existing valid copy.
• We only need to collect W-9s for payments, not reimbursements. Make sure these reimbursements do NOT get counted as payments.
• We will need to group all payments (across all orgs) by their entity so that we can issue 1099s at the end of the year

### Tasks
- [ ] Explore Gusto for collecting W-9s and W-8 BENs
- [ ] How do we securely handle this information?

Learnings

• The only way to uniquely identify an entity is via their W-9/W8 BEN information. Emails, names, etc. won't cut it.
  • This means we need a way to parse W-9s or have people fill out W-9s on HCB so we have accurate SSN/EINs

[YodaLightsabr]

Would this be done through Gusto?