Refactor ble advertising to capsule & kernel hil

[cpluss]

Pull Request Overview

Refactor of the nrf5x BLE advertising driver to capsules, and the BLE advertising hil into the kernel hil.

No logic changed, just refactored into different cargo containers.

I think this is the correct locations, but might be wrong :)

Formatting

• Ran make formatall.

[bradjc]

Just a note, we setup the git pr template because it helps with getting things in order before submitting a pull request. In this case updates to the documentation are required because we have a list of capsules in the README to help users find what Tock supports (looking through a folder of 40-odd, sometimes cryptic file names is a little daunting), and adding a new capsule requires updating the list.

I pushed a commit that adds the link, but in the future it would be helpful if you left those checkboxes there.

[cpluss]

@bradjc thanks! I'll think about this in the future :) This PR was a bit rushed on my part

[niklasad1]

LGTM!

But I leave the last word to @alevy because he had some concerns putting the ẀIP HAL in the capsules previously that's why is it in ǹrf5x currently

[alevy]

@niklasad1 I think the concerns I used to have about that are less important now that we have more formalized ways of listing which parts of the repo is stable and which is in flux. Plus, now that we have another BLE chip coming along, any issues with the interface not being generic enough should pop up quickly.

[alevy]

We'll almost certainly want to rename the HIL to ble_radio or something more general than just advertising, but moving to capsules as-is is a good first step as well.