Discussion: Improve knowledge and documentation of controllers and estimators state

[gemenerik]

We support a variety of controllers and estimators in the firmware, but currently we do not have a good understanding of their state. In practice, only the default controller and estimators are tested regularly in real life.

We should have a discussion about:

• The criteria for including controllers and estimators in the firmware
• What level of maintenance and testing they deserve
• Whether we can improve our knowledge or testing of them without spending excessive time
• If we should clarify/document which controllers/estimators are actively maintained and which are not
• The pros and cons of supporting a wide variety, even if some are only lightly tested (e.g., at least they compile, so they are easy to revive)
• How to document the current state of each controller and estimator
• A plan for how to better manage all different controllers and estimators

Related to #573 (improving the INDI controller)

Goal:

• More clarity on the state of different controllers and estimators
• A concrete plan for managing and documenting them going forward