Allow support/readonly roles to access AWS Sustainability

[cadmiumcat]

What problem does this pull request solve?

We're giving the support and readonly roles permission to access the Sustainability console (so that we don't have to use the admin role). These are only read permissions so it's ok for the readonly role to also have them.

We're combining some policies so that we don't exceed the maximum number of policies per role (10)

Trello card:

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Has all relevant documentation been updated?

Reminders

If you've made changes to the deployer role (files in modules/deployer-access):

• Remember to run make <environment> forms/account apply on the relevant environments (dev, staging, user-research, and/or prod)
• Check the #govuk-forms-deployment-notifications Slack channel to ensure the apply-forms-terraform-<environment> pipelines have run successfully