hyper: refactor, update Rust, Hyper, and deps (TechEmpower#9720)

* hyper: refactor, update Rust, Hyper, and deps

- Update Rust to 1.85.0
- Update hyper to 1.6.0
- Use socket2 instead of net2
- Bump other dependencies
- Remove hyper-db test. This is now provided as a route in the main test.
- Add a new test using tokio multi-thread runtime to compare with the
  single-thread runtime. This uses the same docker image, but passes a
  command line argument to the server to use the multi-thread runtime.
- Add a healthcheck /ping url to the dockerfile to ensure that the
  server is running before running the tests.
- Use deadpool-postgres for connection pooling.
- Use cached prepared statements for the queries.
- Factor each test into its own module.
- Simplify the previous approach that used closures into more a more
  straightforward approach that uses linear functions.
- Add single query and multiple query tests.

* hyper: add maintainers

* fix: don't pre-compute json content-length

* fix: add back socket.set_nodelay(true)

* fix: don't precompute plaintext content-length header

Author: joshka

frameworks/Rust/hyper/.dockerignore

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+target/