Tempus 919 kv entry with unit

[shgupta22]

User Story: #919

PR contains the following:

1. Schema changes for TS, DS and Attribute tables
2. Model and Entity changes for supporting Unit tag with timeseries, depthseries and attributes data.
3. Doing unit conversion of incoming data before storing in DB. Conversion is done by using the unit-conversion library.
4. UI changes for displaying units with data.
5. WebSocket Subscription changes for converting the unit to SI system.
6. Integration tests for UnitConversion Service and new tests for ts, ds and attribute service with units

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[anuj-akt]

As discussed, move unit conversion logic to transport layer.