New worker, Search for BT LE tag

[mredone]

New idea.
Add new worker to search specific BT LE tag mac address and send it via mqtt as presence detection HOME/AWAY.

Now i use room-assistant on RPi0W with home assistant.
It send a lot information about BLE TAG (i have cheap iTAG).
For presence we need only a is a specific mac in range.
For not flooding mqtt broker it will check is any change and change is send to broker.

[bbbenji]

Great idea:) looking forward to your PR!

[jumping2000]

Very nice feature!! I hope someone will implement it!

[mredone]

Great idea:) looking forward to your PR!

Yeah. I can test, i can help but my coding is soooo lame :)

[zewelor]

@mredone after merging this is should be supported: 345b200.