suggestions for the "espressif/ble_ota" component

[koltinov]

I suggest

1. Provide for the possibility to change the standard device name. right now it's "nimble-ble-ota" on all devices. if there are several of them, then it is difficult to distinguish them, you need to know the MAC. if it is possible to give different names, it will be better.
2. In the application, add a display of the firmware download progress.