Updated entity handling

[patrickvorgers]

Added and changed the following entity handling

• Automatically enable/disable heatpump 2 (duo installation) entities during setup
• Fixed statistics for temperature/power/flowrate entities
• Corrected flowrate unit_of_measurement from l/h to L/h
• Disable diagnostic entity "Timestamp last update" by default because of the number of logbook entries
• Changed the handling of the COP entities when the heatpump is not producing heat. The heatpump still uses around 5 W so based on the formula: CoP = power produced / power input => 0 = 0 / 5
• Updated calculation of COP and Heatpower sensors so that they can be used for Quatt Duo. The orginal sensors have been renamed because of the limited scope of HP1

[patrickvorgers]

@marcoboers can you have a look at this PR?

[marcoboers]

Thanks! This is looking good!