Unify Project Set Changes / Updates

Currently, after a Project Set is deployed, any changes require manual modification of each respective `main.tf` file. For example, if a change is made to the `azure-lz-vending` template file, these changes are not applied to the existing Project Sets, and only affect net-new Project Sets.

We need to investigate, research, and discuss the best at-scale/long-term approach for applying and unifying changes across existing Project Sets. Additionally, this work could include investigation on how to still allowing for customizations to a Project Set.

## Acceptance Criteria
> Generated by [Zenhub AI](https://www.zenhub.com/ai)

- [ ] **Scenario: Unify Project Set Changes / Updates**
- Given the current manual modification of each `main.tf` file after deployment
- When changes are made to a template file, such as `azure-lz-vending`
- Then the issue should be resolved by implementing an at-scale/long-term approach for applying and unifying changes across existing Project Sets while still allowing customizations.

Review the deployed Project Sets and their respective main.tf files, then compare them with the azure-lz-vending template. Investigate how template changes could be applied at scale while preserving Project Set customizations. Done means an agreed and implemented long-term approach replaces manual updates across existing Project Sets.

Written by the indexing model from the issue text.