feat: update metrics on save_blocks

[joshieDo]

Adds metrics for save_blocks and commit operations.

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PR Stack

#21045 (metrics) ◀  #21003 (rocksdb)
         \           /
          \         /
           #21012 (account changesets)
              ↓
           #20993 (parallelize save_blocks)
              ↓
            main

• feat: update metrics on save_blocks #21045 ◀
• feat: add rocksdb to save_blocks #21003
• feat: enable account changesets on save_blocks #21012
• feat: parallelize save_blocks  #20993

[codspeed-hq]

Merging this PR will not alter performance

✅ 118 untouched benchmarks
⏩ 7 skipped benchmarks¹

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_{Comparing joshie/par-save-metrics (337d14d) with joshie/par-save-blocks-acc-cs (e7cf1f8)}

Footnotes

1. 7 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩