Enhance documentation with emphasis on Business objects, not only dicts

[guilieb]

Is your feature request related to a problem? Please describe

In the current documentation, the examples are written using plain old dictionaries. As a rule engine, if we process business objects, it might be better to treat these business objects as mapping to be used in the input_data directly.

Describe the solution you'd like

Update documentation with a new section describing the process of using business objects as mapping.

Describe alternatives you've considered

Update the ARTA framework itself to convert any business object as a mapping, but the responsibility should not be taken by the framework but the framework’s users.