Add maximum encryption key size to PairingDelegate

[jmdietrich-gcx]

So far the maxmium encryption key size has been hardcoded to 16 bytes in 'send_pairing_request_command()' and 'send_pairing_response_comman()'. By making this configurable via the PairingDelegate, one can test how devices respond to smaller encryption key sizes. Default remains 16 bytes.

[barbibulle]

The code looks fine. Can you run the formatter before we can merge it? (see the automated checks for details on the formatting errors)

[jmdietrich-gcx]

Fixed the code formatting in a new commit. Should I squash the new commit?

(Is VS Code supposed to auto format on save using the devcontainer?)

[barbibulle]

Fixed the code formatting in a new commit. Should I squash the new commit?

(Is VS Code supposed to auto format on save using the devcontainer?)

No need to squash. For formatting, I haven't checked the settings in the devcontainer. We use black as the formatter. I usually have my VSCode settings do that automatically for me, but you can also run invoke project.format from the top level of the repo, what will invoke the formatter for you.