Add option to select hci adapter

[Lenart12]

Description

In this PR I implement the proposed changes in #373, but without actually switching bluetooth library. This is done so we can prepare library for the backing bluetooth library switch (if it ever happens). Along the way we also got some of the same bonuses that are mentioned in that PR.

Mainly:

• Allowing us to select a different hci device (Solves stuck Scan and pick first available hci device #369)
• Simplified adapter error handling
• Exchange MTU to determine block size
• Updated ble example

Tested with RPI 4B+

Type of change

Please select all options that apply to this change:

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Bug fix (non-breaking change which fixes an issue)
• Documentation update

Checklist:

Confirm you have completed the following steps:

• My code follows the style of this project.
• I have performed a self-review of my code.
• I have made corresponding updates to the documentation.
• I have added/updated unit tests to cover my changes.

[pkuehnel]

Can you please update the docs as well? There are so many undocumendet changes, e.g.

• Scan for vehicle, instead of sending a command
• Timeouts for vehicle scan/command execution

[Lenart12]

Im confused, there was no changes to any timeout logic. Which parts are you refering to? Maybe your first item is refering to the examples/ble utillity, which has updated docs in regards to -scan-only switch. For the second item, i dont know.