Implement pooled resource item reset when given back

[jpraynaud]

Content

When resources are given back to a resource pool (e.g. Merkle maps in the Cardano transaction prover), they need to be reset properly (e.g. the Merkle map should be compressed so that all its values are represented by their root). This will guarantee that pooled resources are consistent and do not depend from previous computations. (e.g. this will avoid the risk of memory overflow and provide a consistent proving time).

This PR includes:

• A Reset trait to be implemented by pooled resources of the ResourcePool (with a blanket implementation).
• Implementation of the Reset trait by the MerkleMap with a compression of the provable values to their root.

Benchmarks

Total Requests	Concurrency	Transactions/Request	Pool (x50) : Request/s	Pool (x50) + Reset given back pooled MKMaps: Request/s
1000	100	1	1380.67	1378.26
1000	100	2	472.86	472.56
1000	100	3	294.02	289.8
1000	100	4	255.05	247.36
1000	100	5	160.5	148.61
1000	100	6	142.99	141.09
1000	100	7	117.91	117.81
1000	100	8	107.07	105.44
1000	100	9	85.94	85.38
1000	100	10	86.75	83.74

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] CHANGELOG file is 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)

Closes #1743

[github-actions[bot]]

Test Results

    3 files  ±0     43 suites  ±0   8m 52s :stopwatch: +12s 1 036 tests +1  1 036 :white_check_mark: +1  0 :zzz: ±0  0 :x: ±0  1 134 runs  +1  1 134 :white_check_mark: +1  0 :zzz: ±0  0 :x: ±0 

Results for commit 80dc8176. ± Comparison against base commit 0c3ee098.

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