[BREAKING] Refactor NimBLEDevice

[h2zero]

• General code cleanup
• NimBLEDevice::getInitialized renamed to NimBLEDevice::isInitialized.
• NimBLEDevice::setPower no longer takes the esp_power_level_t and esp_ble_power_type_t, instead only an integer value in dbm units is accepted.
• NimBLEDevice::setPower now returns a bool value, true = success.
• NimBLEDevice::setMTU now returns a bool value, true = success.
• NimBLEDevice::getAddress will now return the address currently in use.
• NimBLEDevice::init now returns a bool with true indicating success.
• NimBLEDevice::deinit now returns a bool with true inidicating success.
• NimBLEDevice::setDeviceName now returns a bool with true indicating success.
• NimBLEDevice::setCustomGapHandler now returns a bool with true indicating success.
• NimBLEDevice::setOwnAddrType now returns a bool with true indicating success.
• NimBLEDevice::setOwnAddrType will now correctly apply the provided address type for all devices.
• NimBLEDevice::setOwnAddrType no longer takes a bool nrpa parameter.

Fixes #212 Fixes #203