Unify exporters API with common processing functionalities

[ahmdmhd]

The current exporters share some common processing functionalities:

1. Schema loading
2. Naming configuration
3. Selection query
4. Output generation

However, some exporters (jsonschema and protobuf) implement processing functionalities that are not common between other exporters:

1. Root type filtering
2. Instance expansion

This issue proposes adding the missing processing functionalities to the remaining exporters. Unifying the exporters APIs allows for consistency between the export commands.