feat: Idempotency helper utility

[to-mc]

Issue #, if available: #218

Description of changes:

Implementing RFC #218. I'll be working together with @igorlg on this.

Todos

• Implement caching
• Update caching implementation with LRU / max size
• Review/replace error handling implementation (especially the pickle bit, which currently causes security baseline to fail the build)
• Add unit tests and complete integration tests
• Review/remove table creation logic/implementation
• Add logging
• Add docs
• Add payload validation
• Improve exception handling for unrecoverable errors from persistence layer

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-io]

Codecov Report

Merging #245 (d17275d) into develop (fc08062) will decrease coverage by 0.51%.
The diff coverage is 93.90%.

@@             Coverage Diff             @@
##           develop     #245      +/-   ##
===========================================
- Coverage    99.75%   99.23%   -0.52%     
===========================================
  Files           79       85       +6     
  Lines         2859     3138     +279     
  Branches       119      151      +32     
===========================================
+ Hits          2852     3114     +262     
- Misses           5       14       +9     
- Partials         2       10       +8     

Impacted Files	Coverage Δ
aws_lambda_powertools/shared/cache_dict.py	71.42% <71.42%> (ø)
...da_powertools/utilities/idempotency/idempotency.py	92.53% <92.53%> (ø)
...wertools/utilities/idempotency/persistence/base.py	95.16% <95.16%> (ø)
...ambda_powertools/utilities/idempotency/__init__.py	100.00% <100.00%> (ø)
...bda_powertools/utilities/idempotency/exceptions.py	100.00% <100.00%> (ø)
...ools/utilities/idempotency/persistence/dynamodb.py	100.00% <100.00%> (ø)
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fc08062...d17275d. Read the comment docs.

[michaelbrewer]

Just some comments so far.

[michaelbrewer]

@cakepietoast I added some updated comments.

[nmoutschen]

Question: Should we explain how it'll work under the hood here? This could help clarify how often this will call DynamoDB, what parameters it'll look at to decide if it's an idempotent request or not, etc.

Question: Should we mention how this stores the event into DynamoDB?

[to-mc]

I think if we address this it should be in the documentation. Happy to make changes to the docs based on feedback!

[nmoutschen]

LGTM for the doc. Just 2 nitpicks, but these can be changed in the future.

[michaelbrewer]

Small review changes