[Spike] Investigate solutions to restrict purchases on AWS Marketplace

**Describe the Issue**
We are not allowed to purchase services on AWS Marketplace. Yet, it is still technically possible to purchase them, and we don't have much control over this.

**Additional Context**
By restricting we mean having product teams come through us to complete the purchase. If the service is free, we will allow the purchase right away, if the service is paid we will check that a) the team completed competitive procurement and b) we have sufficient funds in our account with SSC to cover this unplanned expense
**Acceptance Criteria**

- [ ] Investigate possible solutions to restrict purchases on AWS Marketplace
- [ ] Present solutions to Olena & Thibault

Start by investigating AWS Marketplace controls that could require product teams to route purchases through the stated review process. Compare how free and paid purchases would be handled, including procurement and SSC funding checks, then present the possible solutions to Olena and Thibault.

Written by the indexing model from the issue text.