Multithreaded Decryption

[tyurek]

Adds a seq_join and async_move to the shard code operating on encrypted report streams to make decryption parallelizable.

To make sure it is in fact running in multiple cores, I added a print line to the lambda that calls the decrypt function and tested with the multi-threading feature
cargo test --package ipa-core --test hybrid --no-default-features --features "cli compact-gate web-app real-world-infra test-fixture relaxed-dp multi-threading" -- test_hybrid --exact
Example output:

thread id: Thread { id: ThreadId(12), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(8), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(8), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(9), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(12), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(12), name: Some("query-executor"), .. }
thread id: Thread { id: ThreadId(8), name: Some("query-executor"), .. }

[codecov]

Codecov Report

Attention: Patch coverage is 95.81152% with 8 lines in your changes missing coverage. Please review.

Project coverage is 93.08%. Comparing base (ff37b8a) to head (8496b46).

Files with missing lines	Patch %	Lines
ipa-core/src/report/hybrid.rs	91.01%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1490      +/-   ##
==========================================
+ Coverage   93.06%   93.08%   +0.01%     
==========================================
  Files         239      237       -2     
  Lines       43546    43605      +59     
==========================================
+ Hits        40526    40588      +62     
+ Misses       3020     3017       -3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.