HM10: add beacon, better parsing, more

[Staars]

Description:

• a lot better usage of the scan data from the HM10 by doing a stream parsing while reading from serial
• nearly as a by-product added the beacon function very similar to the MI32 (4 beacons, added TX power level)
• updates for HASS ('null' for not received sensor data)
• CGD1 can be used passive now
• turning on autoscan by default (plan is to read active/via connections in future versions only if enabled by the user at runtime)

Checklist:

• The pull request is done against the latest dev branch
• Only relevant files were touched
• Only one feature/fix was added per PR.
• The code change is tested and works on Tasmota core ESP8266 V.2.7.4.5
• The code change is tested and works on core ESP32 V.1.12.2
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass