Commands for rover program, import/export PVOutput, GraphQL improvements

Many new features are included in this release:

Rover:

• You can define commands similar to the mate program. These can turn on and off the load from the android application
• Rover's isNewDay fixed (this fixes a bug that other code that relied on this such as GraphQL and the android application)

PVOutput:

• Import/export values correspond to buy/sell values from FX

GraphQL:

• FX Timers added
• Daily kWh queries
• Query all solar devices and charge controllers

Request:

• Battery voltage only packet to be used with the Arduino program

Message

• "lowbatteryvoltage" event now has "time" field to be used to only alert when voltage has been below for a number of seconds.

Some of these new features don't have great documentation yet. If you are interested in them but are unable to figure out how to use them, please create an issue.