r3-metaevt-maker should get initial state after boot

[btittelbach]

Problem

after smsgw reboot, all door locks need to be actuated in order for r3-metavt-maker to again get a complete state and correctly calculate presence state.

Naive Solution

r3-metaevt-maker should somehow get or query the current state of locks on start

Subproblems

• door lock/ajar messages are not retained in mqtt, out of concerns that this would produce problems. But we might enable retain-flag in all sensor daemons as a test
  • retained message are not saved to a persistent file by mosquitto on smsgw.realraum.at/mqtt.realraum.at in order to protect the microSD, so after smsgw reboot they would be lost anyway

planned solution

• all sensor daemons should send current state on sensor-daemon startup
• define mqtt message that all sensor-daemons listen to, which triggers re-sending of current state
• OR send all ajar/lock message with retain-flag and persist state on smsgw microSD
• modify µC sensor firmware so current state can be queried. Currently most firmware only sends state changes