Adds Tuya Climate temperature multiplier

[jesserockz]

Description:

Some tuya based climate devices report the temperature with a multiplied factor. Tuya only uses int as its data type so this is required to get .5 values.

[17:14:11][C][tuya:023]: Tuya:
[17:14:11][C][tuya:032]:   Datapoint 1: switch (value: OFF)     -- on/off
[17:14:11][C][tuya:034]:   Datapoint 2: int value (value: 42)   -- setpoint (21)
[17:14:11][C][tuya:034]:   Datapoint 3: int value (value: 47)   -- current temp (23.5)
[17:14:11][C][tuya:034]:   Datapoint 102: int value (value: 44) -- current floor temp (22)

Related issue (if applicable): fixes

Pull request in esphome with YAML changes (if applicable): esphome/esphome#1276

Checklist:

• Branch: next is for changes and new documentation that will go public with the next ESPHome release. Fixes, changes and adjustments for the current release should be created against current.
• Link added in /index.rst when creating new documents for new components or cookbook.