Introduce blockgen as an optimization target

[blt]

What does this PR do?

This commit introduces a new binary to the project 'blockgen' which is rigged to
read a lading.yaml and generate the block cache for that config, doing nothing
more. This allows us to use tools like hyperfine, perf etc to debug performance
problems at a macro level, as opposed to a reliance directly on criterion
benchmarks.

With the added example config we have from hyperfine:

Benchmark 1: ./target/release/blockgen examples/lading-otel-metrics.yaml
  Time (mean ± σ):      1.705 s ±  0.018 s    [User: 1.628 s, System: 0.070 s]
  Range (min … max):    1.689 s …  1.751 s    10 runs

Motivation

REF SMPTNG-659

[blt]

• Introduce tag generator into OTel metrics payload #1340 : 2 dependent PRs (#1341 , #1342 )
• Add configuration validation for OTel metrics #1339
• Bound contexts in Opentelemetry Metrics #1337
• Make tagset generation generic #1336
• Generate units according to OTel required spec #1335
• Generate OTel metrics with context limits #1331
• Migrate OTel/dogstatsd common functions to src/common #1329
• Convert opentelemetry_metric to use MemberGenerator method #1326
• Introduce RejectSet #1347
• Introduce blockgen as an optimization target #1346 👈 (View in Graphite)
• main

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[scottopell]

isn't this pretty similar to https://github.com/DataDog/lading/blob/main/lading/src/bin/payloadtool.rs ?

[blt]

isn't this pretty similar to https://github.com/DataDog/lading/blob/main/lading/src/bin/payloadtool.rs ?

Lol yep. I'd recorded "Generator failed to generate..." in my notes but didn't realize it was not a one-off tool that made it. I'll compare and adjust this PR or remove it.