Telemetry DB: Add support for storing the routing path for telemetry data items

[rtamalin]

When persisting telemetry data items in the Telemetry DB we should include the calculated route path #3 (or a reference to it) in the telemetry data item table.

The simplest approach, from a relational perspective, would probably be to add a new routing path table, and new routing paths to it, and then add a routing path id field to the telemetry data table with a foreign key reference to the routing path.

Alternatively, if we don't want to create a separate routing path table, and don't want to have to store an arbitrary sized routing path value, we could store a hash, e.g. SHA256, of the routing path value, with the extremely low risk of multiple routing paths potentially hashing to the same hash value.