Enable / disable pairing+bonding

[benjaminaigner]

Currently, it is not possible to deny any pairing requests.

We should include the possibility to deny pairing requests by default and enable them by a command via the external UART.

As there is no useful documentation how to do that,
I think it should be sufficient to deny an authentication request here

esp32_mouse_keyboard/main/ble_hidd_demo_main.c

Line 244 in f27a45a

esp_ble_gap_security_rsp(param->ble_security.ble_req.bd_addr, true);

by returning false.

Nevertheless, if we switch OFF pairing by default, it would break compatibility.
So I suggest we enable this feature by a new KConfig file.

[benjaminaigner]

Unfortunately, the whitelist approach should work in general, but this is currently broken in esp-idf:
espressif/esp-idf#2262

[benjaminaigner]

Maybe there is a solution: espressif/esp-idf#8613