Limit Cassandra Support to Only Telemetry data

Currently, Tempus provides support for Postgres and Cassandra databases. The choice can be made at install time. Once chosen 'all' data - system metadata, as well as Telemetry and Depth series data is stored in the chosen database.

This requires code level support for both databases. Due to intrinsic differences between SQL and No-SQL, this often means parallel development for both, which significantly increases Tempus development effort and time.

It is therefore, proposed that all system metadata - BU's, data models, assets, devices etc be stored only in Postgres. The users will have a choice of Postgres or Cassandra, only as far as storage of Time Series and Depth Series data is concerned.

This User Story is created to initiate work required to separate the two. Its goal is to ensure that there is no loss of functionality to any Tempus user, in case, they choose Cassandra to store Telemetry data.

The first steps towards this goal would be identification of changes to be carried out in Tempus and then planning out those tasks.