Define project goals and non-goals

[Racer159]

Describe what should be investigated or refactored

We need to define project goals / non-goals so that we can show where we may or may not mesh with Zarf and it's actions code.

This should cover:

• Task sharability (currently the ability to include remote tasks and share them across repos has proven very useful)
• Task portability (being able to run tasks on Linux/macOS (and likely Windows in the future) is something we want)
• Execution flexibility (being able to execute across a variety of modes (local commands, remote commands, scripts)
• Pipeline security (being able to sanitize the environment when running security relevant pipeline stages)

Additional context

Currently we are API compatible with Zarf actions through the BaseAction struct - Zarf is also looking to simplify actions so we will need to determine where our goals mesh to define the best way to integrate. This could look like:

1. Maintaining BaseAction as the interface with Zarf with Zarf eventually directly including it in their zarf.yaml spec
2. Removing BaseAction as the interface with Zarf and instead providing an entrypoint at the task file level (i.e. Zarf just includes the task file in a package and then calls maru like uds run does).
3. Zarf implements a plugin system and Maru is included in a container or in the plugin format Zarf chooses
4. Zarf and Maru do not integrate and each project goes their own way.
5. Zarf and Maru do not integrate and Maru is killed in favor of Dagger.

[oates]

We should move this to a design doc and move out.