Make Cardano transaction prover able to certify more than 5 transactions

[jpraynaud]

Content

This PR includes a fix to make the Cardano transaction prover able to certify more than 5 transactions.

Benchmarks

Total Requests	Concurrency	Transactions/Request	Pool (x50): Request/s	Pool (x50) + Optimization 'get_all_transactions_for_block_ranges': Request/s
1000	100	1	233.7	256.29
1000	100	2	170.75	181.31
1000	100	3	127.82	135.56
1000	100	4	99.07	112.84
1000	100	5	83.36	94.28
1000	100	6	0	78.23
1000	100	7	0	69.29
1000	100	8	0	60.99

Running on Linux / 8 cores / 64 GB RAM / 2 TB SSD

Pre-submit checklist

• Branch
  • [x] Tests are provided (if possible)
  • [x] Crates versions are updated (if relevant)
  • [x] Commit sequence broadly makes sense
  • [x] Key commits have useful messages
• PR
  • [x] No clippy warnings in the CI
  • [x] Self-reviewed the diff
  • [x] Useful pull request description
  • [x] Reviewer requested

Issue(s)

Relates to #1722

[github-actions[bot]]

Test Results

    3 files  ±0     43 suites  ±0   8m 35s :stopwatch: -1s 1 003 tests ±0  1 003 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0  1 101 runs  ±0  1 101 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit c188939d. ± Comparison against base commit adec3249.

:recycle: This comment has been updated with latest results.