Update get reference description

[dt-woods]

To accommodate the latest metadata improvements, this reference description is expanded to the following:

• Process Type: State whether this is a Unit Process or System Process
• Inventory Method: State whether this is Attributional or Consequential
• Technology Type: High level technology categorization, such as natural gas, or bio fuels
• Unit Process Boundary: State whether the process is Cradle-to-Grave, Cradle-to-Gate, Gate-to-Gate, etc.
• Co-products: List names, if applicable; otherwise, N/A
• Co-product allocation: If applicable; otherwise, N/A. Examples include system expansion and mass allocation; list what is used and if there are any restrictions.
• Scenarios: Yes or no
• Location: Geographic region associated with the unit process
• Valid From: Year or date format
• Valid Until: Year or date format
• Unit Process Creation Date: When the process was created (date format)
• Data Quantity Score: The process DQI score (may also return the name of the DQI method)
• Data Completeness: (may be helpful to return the text from 'Data Completeness', 'Data Selection', 'Data Treatment', 'Sampling Procedure', and 'Data Collection Period' metadata fields)

[dt-woods]

NOTE: several bits of this come from format_process_doc method.