Save models to yaml or similar to work around security risks when sharing models

[RubendeBruin]

Issue:
When sharing models with a client via a .dave file the code in the .dave file is executed on the machine of the client. This is a security risk.

Proposal:

• Disable all code-running facilities in DAVE viewer program.
• Save the model to yaml or similar instead and load from there.

Implementation:

• Mark all primary setters for all node types with a tag, for example #primary
• Add this to the automatic documentation
• Based on the automatic documentation, create a writer and a reader