[CI]: Epic: fix everything

## Currently known flaky tests (could be a test issue or a nerdctl issue)

New entrants:
- #4322
- #4332
- #4347
- #4363
- #4365
- #4366

Third-party:
- P0: advanced: #3524
- P0: #4142

Possibly EL8 / slow environments specific:
- P1: #4118
- P1: #4068
- P1: #3971

Kube specific:
- P1 (minor, but annoying): #4106
- to be confirmed this is still happening with containerd v2

Test currently disabled (link to documented issue):
- #3437
- #3475
- see TestNetworkInspect (none and host inspection)

"Retry-them" tests that are clearly broken:
- #4141
- #4143
- #4146
- #4147

Others:
- P0: #4066

To confirm:
- #3727

## CI structural issues

- P1: #3733
- P2: #3453

## Tests to add

- #3494
- Expert: #3156
- #1989
- #1957
- #178

## Enhancements: tigron

- #4029
- #4028
- #3448

## Enhancements: generic

- dockerfile specific: #4031
- dockerfile specific: #4021
- #3858
- #3845
- #3480
- #3303
- #3257
- fix unit tests so that we can `race` them

## Performance tracking

- Latest major disruption: #3924
- #3577

## Ongoing work

Evergreen playground:
- #4129

CI work in progress:
- #3636
- #3579