blescanmulti - improve scanners options (#56)

* Helpful utils that will allow to reduce common code

* Update config with new options for blescanmulti

* Default values for blescanmulti if not provided by config file

* Allow to configure scan behavior

* Allow to configure returned payload

* Initial version of saving last state

* Support class that will remember last status of device

* Add docs for available options

* Move scanner to instance, this will prevent recreating it each time it is required to scan

* Use items instead of values. We require here to have pair of key and value, not just value

* Make sure that mac address is in lower case

* Optimize searching for devices, use hash maps

* Remove unused method

* Because YAML is already doing some conversions this change will allow to always get proper value

* Fix issue. Mac address and name was provided in wrong order

* Use worker to format topic

* Send also RSSI info

config.yaml.example

@@ -54,6 +54,12 @@ manager:
           beacon: 00:11:22:33:44:55
           smartwath: 00:11:22:33:44:55
         topic_prefix: blescan
+        available_payload: home
+        unavailable_payload: not_home
+        available_timeout: 0
+        unavailable_timeout: 60
+        scan_timeout: 10
+        scan_passive: true
       update_interval: 60
     toothbrush:
       args: