Move the TAG definition of each example to the corresponding
source file (previously it is defined in the common example
intialization header file), which can avoid the redefinition
of TAG in some situations.
The existing Bluetooth examples are split as:
1. examples/bluetooth/bluedroid - Bluedroid Host (BT + BLE) examples
a. examples/bluetooth/bluedroid/classic_bt - Classic BT examples
b. examples/bluetooth/bluedroid/ble - BLE examples
c. examples/bluetooth/bluedroid/coex - Classic BT and BLE coex examples
d. examples/bluetooth/bluedroid/hci - VHCI and HCI UART examples
i. Rename ble_adv to controller_vhci_ble_adv and move it in hci folder
2. examples/bluetooth/nimble - NimBLE BLE Host + NimBLE Mesh examples
3. examples/bluetooth/esp_ble_mesh - ESP BLE Mesh examples
4. Update documentation references