Fixes #62 - looks training

[pjabl]

The script facilitates the generation and loading of example and sample data into the BigQuery explore_assistant dataset. The process supports multiple models and explores, relying on a set of looks for each explore in one or more folders in your Looker instance. The output is generated in a tree structure:

• examples
  • model
    • explore

Each look title from the defined folder creates an "input" from a pair of "input"/"output". The following query parameters from the Looker URL are included (only if they are non-empty):

• fields
• filters (f[])
• sorts
• limits
• dynamic_fields
• vis
  • type
  • hidden_fields
  • hidden_points_if_no
  • show_comparison
  • comparison_type
  • series_types

The following parameter is excluded:

• query_timezone
• filter_config
• fill_fields

Support for loading samples into BigQuery has been added to the explore_assistant_samples dataset.