Removed the time_authoritative, time_zone_authoritative, and chunk_size fields.

These fields were determined to be useless. The time and time-zone, if not authoritative, should not abuse their respective fields in the meta-data. The chunk size, which was used for paging, should be an aspect of the system and not something determined by individual schemas.
Updated the DSU RI to the beta specification.

The schemas no longer reference time or time-zone authoritativeness nor do they reference the chunk size.

The "omh/v1" endpoint now returns the set of known schema IDs; the "omh/v1/{schema_id}" endpoint now returns the set of versions for the given schema ID.