Update demos to use new metadata

[amontanez24]

Problem Description

Our demo module should use the new metadata class once #2104 is complete.

Expected behavior

• Add a json for the new metadata structure.
• Write and run a script to update all demo zips to contain the new json structure
• Update download_demo to return the new class

Additional context

• The script to update the metadata doesn't need to be added to the library
• Updating the metadata follows a different set of steps for each modality:

Single table and sequential

• We want to convert the json to that of multi-table metadata. To do this we need to create a dictionary mapping table names to the single table metadata.
  • You can use the csv name as the table name.
• Update the METADATA_SPEC_VERSION

Multi table

• Update the METADATA_SPEC_VERSION