[#849] Configure sanchogov.tools sub-domain for the analytics service

[adgud]

This adds Terraform code that creats "participation" subdomains for each environments. The exception is the beta environment, where DNS records are not handled with TF, but need to be created manually.

List of changes

• Add "participation" subdomain DNS record for each environment.

Checklist

• Configure sanchogov.tools sub-domain for the analytics service #849
• My changes generate no new warnings
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the changelog
• I have added tests that prove my fix is effective or that my feature works