Ble add blescan mode

[fellev]

Description:

Implemented a new BLEScan mode:
BLEScan2 nn - Initiates a manual scan for nn seconds and publishes results on tele when at least one device is detected.
This feature is useful for receiving immediate notifications from the Tasmota device when a device is found, without waiting for periodic telemetry messages.

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.8
• The code change is tested and works with Tasmota core ESP32 V.3.1.0.241117
• I accept the CLA.

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