Add primer CI tool 🏴 (#1402)

Add primer CI tool 🏴 (#1402)

* Add primer CI tool 💩
- Run in PATH `black` binary on configured projects
- Can set wether we expect changes or not per project
- Can set what python versions are supported for a project
- if `long_checkout` True project will not be ran on CI

Will add to CI after I finish unit tests to avoid silly bugs I'm sure I have 🤪

Tests:
- Manual Run - Will add unit tests if people think it will be useful
- Output:

```shell
(b) cooper-mbp1:black cooper$ time /tmp/b/bin/black-primer -k -w /tmp/cooper_primer_1
[2020-05-10 08:48:25,696] INFO: 4 projects to run black over (lib.py:212)
[2020-05-10 08:48:25,697] INFO: Skipping aioexabgp as it's disabled via config (lib.py:166)
[2020-05-10 08:48:25,699] INFO: Skipping bandersnatch as it's disabled via config (lib.py:166)
[2020-05-10 08:48:28,676] INFO: Analyzing results (lib.py:225)
-- primer results 📊 --

2 / 4 succeeded (50.0%) ✅
0 / 4 FAILED (0.0%) 💩
 - 2 projects Disabled by config
 - 0 projects skipped due to Python Version
 - 0 skipped due to long checkout

real	0m3.304s
user	0m9.529s
sys	0m1.019s
```

- ls of /tmp/cooper_primer_1
```
(b) cooper-mbp1:black cooper$ ls -lh /tmp/cooper_primer_1
total 0
drwxr-xr-x  21 cooper  wheel   672B May 10 08:48 attrs
drwxr-xr-x  14 cooper  wheel   448B May 10 08:48 flake8-bugbear
```

* Address mypy 3.6 type errors
- Don't use asyncio.run() ... go back to the past :P
- Refactor results into a named tuple of two dicts to avoid typing nightmare
- Fix some variable names
- Fix bug with rebase logic in git_checkout_or_rebase

* Prettier the JSON config file for primer

* Delete projects when finished, move dir to be timestamped + shallow copy

* Re-enable disabled projects post @JelleZijlstra's docstring fix

* Workaround for future annotations until someone tells me the correct fix