[Feature-Idea] Device info dump

[FaBjE]

Note: This is a new feature idea, I don't know if I will find the time to implement this, anyone is welcome to do so

Rationale
When getting a new/unknown BLE device it always a discovery which services/characteristics are implemented/supported.
Especially in reverse-engineering of a undocumented product.

Description
Currently it is technically possible to do this by hand, but I think it would be a good feature to have a "device info dump" command.
Listing all the available services and their characteristics with their values/options in one big list.

Implementation
There is a bit of a challenge implementing this in the current codebase.
Only the BluetoothLEAttributeDisplay is stored in the global _services and _characteristics lists. Also the _characteristics is switches based on the selected service.

We could either:

• Store all services as a "nested list" like structure. with each of them having a list of their characteristics as a "child" property/list and let other commands use that "tree". _selectedService and _selectedCharacteristic would point to objects within that list.
• Implement the command with kind of a duplicate code of the current service selection/switching. which would duplicate a lot of code.