Draft: Add Access Tokens Policies blueprint
What does this MR do and why?
Adds a new blueprint for Access Token Policies.
Read this proposal here: https://gitlab.com/gitlab-org/gitlab/-/blob/access-tokens-policies-blueprint/doc/architecture/blueprints/access_tokens_policies/index.md
Closes https://gitlab.com/gitlab-com/gl-security/security-architecture/general/-/issues/9
Edited by Philippe Lafoucrière