Epic: Permission sharing & duplication across entities

This issue is to track the delivery of items related to improving the management of user permissions. The key requirements that should be completed as part of this epic (although they need scoping and designing) are:

1. Adding roles and permissions to the terraform provider
2. Adding the ability to create permission or role templates, so that when new projects or environments are created, the already defined roles are applied to the new project / environment

### User stories (WIP)

- As an administrator of Flagsmith, when I create a new environment, I want permissions to be automatically applied based on a configured set of rules
- As an administrator of Flagsmith, when I create a new project, I want permissions to be automatically applied based on a configured set of rules