Make all propagations async

[GeoffreyHuck]

Related to #1047 (First step of: Make sure async propagation does not block other requests).

The async propagation, when executed async or sync when there's no endpoint or an error during its call, always execute the following propagations:

• items_ancestors
• permissions
• results

There were tests that checked things like "verify that the results propagation has been run but not the permissions propagation. Those tests have been updated because it cannot happen anymore.

Note: The groups ancestorpropagation is an exception. It is always executed in sync because there are cases where its results are used in intermediate computations. Since it's very fast compared to the others, it shouldn't be a problem.

Review

Easier to review commit by commit as there are a few steps. Details in commit messages.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (dd140bf) to head (27d5a62).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## 1081 #1100 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 239 239 Lines 14480 14483 +3 ========================================= + Hits 14480 14483 +3 ```

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