Bugs/parquet created at 179252091

[rosalinekarr]

Problem

Our parquet schema does not match the spec #179252091

Solution

Update the schema to match the spec

Change summary:

• Added createdAt to the parquet schema for each announcement type
• Added contentHash to the parquet schema for profile announcements
• Added Tombstones to the parquet schema with tests
• Updated types on parquet schema to require all announcement types be defined