feat: Speculative Pool WAL

[bsbds]

Please briefly answer these questions:

• what problem are you trying to solve? (or if there's no problem, what's the motivation for this change?)

  Implements write-ahead-log for speculative pool

• what changes does this pull request make?

• are there any non-obvious implications of these changes? (does it break compatibility with previous versions, etc)

[codecov]

Codecov Report

❌ Patch coverage is 86.98092% with 116 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.99%. Comparing base (e35b35a) to head (efa63a3).
⚠️ Report is 332 commits behind head on master.

Files with missing lines	Patch %	Lines
crates/curp/src/server/sp_wal/mod.rs	78.92%	13 Missing and 34 partials ⚠️
crates/curp/src/server/sp_wal/segment.rs	88.73%	11 Missing and 14 partials ⚠️
crates/curp/src/server/sp_wal/codec.rs	88.57%	15 Missing and 9 partials ⚠️
crates/curp/src/server/sp_wal/error.rs	0.00%	8 Missing ⚠️
crates/curp/src/server/sp_wal/tests.rs	95.78%	6 Missing and 1 partial ⚠️
crates/utils/src/wal/pipeline.rs	66.66%	3 Missing and 1 partial ⚠️
crates/curp/src/server/sp_wal/config.rs	96.55%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #818      +/-   ##
==========================================
+ Coverage   75.55%   75.99%   +0.44%     
==========================================
  Files         180      192      +12     
  Lines       26938    28334    +1396     
  Branches    26938    28334    +1396     
==========================================
+ Hits        20353    21533    +1180     
- Misses       5366     5470     +104     
- Partials     1219     1331     +112     

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