chore(idempotency): remove decorators

[dreamorosi]

Description of your changes

As described in the linked issue, this PR removes the Idempotency decorators from the current implementation which will be soon released as public beta. For more info on why we decided to remove them, please refer to #1553.

Related issues, RFCs

Issue number: #1553

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in areas that should be flagged with a TODO, or hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my change is effective and works
• The PR title follows the conventional commit semantics

Breaking change checklist

Is it a breaking change?: NO

• I have documented the migration process
• I have added, implemented necessary warnings (if it can live side by side)

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[dreamorosi]

@mergify rebase

[mergify]

rebase

✅ Branch has been successfully rebased

[dreamorosi]

Successful integration tests: https://github.com/aws-powertools/powertools-lambda-typescript/actions/runs/5391493794

[am29d]

We should probably also remove references in the documentation.

[dreamorosi]

Good catch Alex, I have updated the README and removed all references.

While there, I also added a section for the Middy Middleware and consolidated the examples under their respective title.
Before it was:

• Usage
  • Function wrapper
  • Middy middleware
• Examples
  • Function wrapper
  • Middy middleware

Now it's

• Usage
  • Function wrapper
    • Example
  • Middy middleware
    • Example

Also, I noticed that the DynamoDBPersitenceLayer and its options were not exported in the API docs, I added it and did a find&replace for s/persistance/persistence/ which was used in some places.

Finally, as a side note, I noticed that when we use intersection types the documentation for those resulting types is not rendered correctly. For instance, even though we wrote the docstring for DynamoDBPersistenceOptions, it's rendered empty:

This is because the actual properties are in the base type.

Apparently this is an intended behavior in typedoc: TypeStrong/typedoc#1021. For now I added a @see and exported+linked the actual types but in a separate issue we should look into whether there's a solution for this.

[dreamorosi]

@am29d addressed the comments, ready for review

[am29d]

LGTM!