feat: add Adapter `retrieve_peripherals` method

[szymonlesisz]

This is empty prerequisite for:

• retrieve connected peripherals (by services uuid) https://github.com/deviceplug/btleplug/pull/437
• retrieve known peripherals (by device identifiers) - i will add the implementation for corebluetooth, windows and linux in following pull requests.

List of platforms where the method could be implemented

	paired/connected visible	retrieve by identifier	retrieve by services
macOS	NO	YES	YES
Linux	YES	YES (default)	YES (default)
Windows	NO	YES	YES
Android	?	?	?

im not familiar with droidplug but im sure it is also possible to implement if needed.