Unified secrets management

As recently experienced, having a bus factor of 1 for critical items like secrets can become a huge blocker for even the most basic of tasks. Given the occasionally transient nature of contributors, we want to make things simple to use and secure.

We need a secrets management solution that:

1. Allows OpCode users and contributors to easily retrieve secrets they are authorized access to.
2. Facilitates automation so that deployments and other system operations can be abstracted so an individual access isn't required to keep things moving forward.
3. Allows revocation of access to secrets.

El issue no indica archivos, pruebas ni puntos de entrada. Empieza por definir y comparar un enfoque de gestión de secretos con respecto a los tres requisitos indicados; después, documenta el diseño elegido, los flujos de acceso y revocación, y cómo funcionará la automatización sin acceso individual.