[CDEC-432] Move Mockable and JsonLog to core

[mhuesch]

Description

Move Mockable and JsonLog into core, so that networking can be freed up. The goal is to let networking float upwards in the dependency graph.

Linked issue

https://iohk.myjetbrains.com/youtrack/issue/CDEC-432

Type of change

• [~] 🐞 Bug fix (non-breaking change which fixes an issue)
• [~] 🛠 New feature (non-breaking change which adds functionality)
• [~] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)
• 🏭 Refactoring that does not change existing functionality but does improve things like code readability, structure etc
• [~] 🔨 New or improved tests for existing code
• [~] ⛑ git-flow chore (backport, hotfix, etc)

Developer checklist

• I have read the style guide document, and my code follows the code style of this project.
• If my code deals with exceptions, it follows the guidelines.
• I have updated any documentation accordingly, if needed. Documentation changes can be reflected in opening a PR on cardanodocs.com, amending the inline Haddock comments, any relevant README file or one of the document listed in the docs directory.

Testing checklist

• [~] I have added tests to cover my changes.
• All new and existing tests passed.
  ^ this PR moves code around & doesn't change functionality. Existing tests should be good enough.

[erikd]

Wow, that is a lot of empty lines. Is that just the way it was in the original file?

[erikd]

It seems that was indeed the case. Weird!

[mhuesch]

Yep 🤷‍♂️ In the spirit of minimal changes I left it. But several of these modules definitely could use tidying up.

[erikd]

As you can see from the dependency graph, the networking package is in this werid place at the bottom of the graph, with nearly everything else depending on it.

This is why there is also networking code in infra and lib. By moving Mockable and the JsonLog stuff to core, networking can be moved up in the graph. After this commit is merged we would then work up the dependency graph replacing the networking versions of Mockable and the JsonLog with the core version until nothing more depends on the networking versions and we can then drop the re-exports.

We do it like this so the transition happens in a number of smaller PRs that are easier to review (this one is by far the worst).

It should also be noted that the dependency graph above is about a week out-of-date and that infra has already been moved up near cardano-sl. When networking is also moved up the graph we would like to move all the networking code to a single package.

[erikd]

I happy with this as it is and @mhuesch has communicated with @avieth who also seems ok with this plan of action but Alex has not as far as I am aware looked at his PR.