Migrate existing models to use frontend parameter validation

The following discussion from !157 (merged) should be addressed:

• @tgaskin started a discussion: (+8 comments)

  We are currently using the ForestFire model for integration tests, but also as a demo where people can see the feature fully implemented. FFM also has several internal checks on the C++ side to check parameter validity, however - should we remove them before merging?

As discussed there, the proposal would be the following:

• For existing models, add parameter validation to the respective model configuration
• Aim for these model configurations to remain self-documenting and easy-to-read
• Where applicable, remove the C++ counterparts of parameter checks as they would be redundant.

To be discussed:

• How best to handle parameters that are inside the cell_manager hierarchy?