Use the thread-local ThreadContext in order to be able to define which contexts get propagated

[FroMage]

This is required by quarkusio/quarkus#18689

Fixes #626

[codecov]

Codecov Report

Merging #635 (4e32565) into main (0e32e0a) will increase coverage by 0.48%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main     #635      +/-   ##
============================================
+ Coverage     89.80%   90.29%   +0.48%     
- Complexity     3010     3025      +15     
============================================
  Files           395      395              
  Lines         11825    11823       -2     
  Branches       1478     1480       +2     
============================================
+ Hits          10620    10676      +56     
+ Misses          623      585      -38     
+ Partials        582      562      -20     

Impacted Files	Coverage Δ
.../context/DefaultContextPropagationInterceptor.java	100.00% <100.00%> (ø)
.../mutiny/context/MutinyContextManagerExtension.java	100.00% <100.00%> (ø)
...smallrye/mutiny/operators/multi/MultiEmitOnOp.java	89.52% <0.00%> (-0.96%)	⬇️
...mallrye/mutiny/operators/multi/MultiFlatMapOp.java	85.98% <0.00%> (+0.31%)	⬆️
...java/io/smallrye/mutiny/helpers/Subscriptions.java	80.66% <0.00%> (+0.55%)	⬆️
...lrye/mutiny/subscription/SerializedSubscriber.java	89.62% <0.00%> (+1.88%)	⬆️
...io/smallrye/mutiny/operators/uni/UniMemoizeOp.java	95.04% <0.00%> (+1.98%)	⬆️
.../io/smallrye/mutiny/helpers/queues/DrainUtils.java	77.77% <0.00%> (+2.22%)	⬆️
...subscription/SwitchableSubscriptionSubscriber.java	97.54% <0.00%> (+2.45%)	⬆️
...tiny/operators/multi/MultiBufferWithTimeoutOp.java	75.63% <0.00%> (+2.52%)	⬆️
... and 7 more

[jponge]

Thanks Steph!