Pull the mapping for Imports and source for each model in a tenant

Currently, the only way to extract the information for Import and source mapping is from individual model through the Anaplan interface. These mappings are very useful to track how the data flows across different models and files. To be able to identify how the data flows using this metadata is going to help eliminate a lot of redundancy in data loads and also eliminate unused mappings, files and import processes which will lead to continuous clean-up of the models.