Call setup_tracing_subscriber_for_test from shotover_process as well.

[rukai]

This is useful for tests that run shotover but without a database behind it.

Additionally this PR enables RUST_LOG env var to control the log level

[github-actions]

1 benchmark regressed. 0 benchmark improved. Please check the benchmark workflow logs for full details: https://github.com/shotover/shotover-proxy/actions/runs/7968793452

                        Change within noise threshold.
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high severe
kafka_codec/decode_request_fetch_drop
                        time:   [377.83 ns 390.60 ns 403.31 ns]
                        change: [+25.918% +33.300% +40.327%] (p = 0.00 < 0.05)
                        Performance has regressed.

[github-actions]

1 benchmark regressed. 0 benchmark improved. Please check the benchmark workflow logs for full details: https://github.com/shotover/shotover-proxy/actions/runs/7982758452

                        No change in performance detected.
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high severe
kafka_codec/decode_request_produce_drop
                        time:   [455.77 ns 468.09 ns 480.41 ns]
                        change: [+28.735% +34.654% +40.402%] (p = 0.00 < 0.05)
                        Performance has regressed.

[github-actions]

3 benchmark regressed. 0 benchmark improved. Please check the benchmark workflow logs for full details: https://github.com/shotover/shotover-proxy/actions/runs/7983259105

Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high mild

cassandra_codec/encode_system.local_query_v4_no_compression
                        time:   [931.10 ns 943.89 ns 957.53 ns]
                        change: [+21.158% +24.606% +28.042%] (p = 0.00 < 0.05)
                        Performance has regressed.
--
Found 6 outliers among 100 measurements (6.00%)
  3 (3.00%) low mild
  3 (3.00%) high severe
cassandra_codec/encode_system.local_result_v4_no_compression
                        time:   [25.208 µs 25.922 µs 26.572 µs]
                        change: [+21.087% +24.140% +27.049%] (p = 0.00 < 0.05)
                        Performance has regressed.
cassandra_codec/decode_system.local_result_v4_no_compression
                        time:   [1.3677 µs 1.3910 µs 1.4140 µs]
                        change: [+22.498% +23.884% +25.395%] (p = 0.00 < 0.05)
                        Performance has regressed.