point to the new jsoncdc

[Mythra]

this commit removes all references to the (now older) jsoncdc. pointing to the new source repo "instructure/jsoncdc". it also installs the latest version of jsoncdc which is available now on the "testing" channel instead of unstable.

this shouldn't break anything with lapidus seeing as how the two changes are:

• We release DEBs now (no impact).
• We have a slightly longer rust line length (If this had an impact I'd be very confused).
• We've added extra info to commits, but haven't removed any existing properties. (Perhaps in the future lapidus should pick up these properties?).
• My editor also removed some whitespace that was in the readme. If you need me to readd these I can.

[jmealo]

@SecurityInsanity: Thanks for the PR. Sorry, I didn't get a notification for this; I'll review this later today.

[jmealo]

@SecurityInsanity: I don't think any of your changes broke the build, but, the CI needs a bit of an overhaul, I'll probably be moving it into a docker container and running it on my GitLab infrastructure. This looks fine to merge.