chore(metrics): Add typeDoc

[flochaz]

depends on #277

Description of your changes

Add typedoc to code to get:

• API documention to get generated

• Get mouse over doc in IDE

How to verify this change

1. generate API docs with npm run docs-generateApiDoc
2. render API docs with npm run docs-runLocalApiDoc
3. Go to http://127.0.0.1:8080/modules/_aws_lambda_powertools_metrics.html

Related issues, RFCs

#151

PR status

Is this ready for review?: YES
Is it a breaking change?: NO

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
• The code coverage hasn't decreased
• I have added tests that prove my change is effective and works
• New and existing unit tests pass locally and in Github Actions
• Any dependent changes have been merged and published in downstream module
• The PR title follows the conventional commit semantics

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[dreamorosi]

Thanks for the PR, left some comments and suggestions around format/styling but looking good. After the beta has been published and we have the docs for all the modules we should make sure all the examples are consistent and use correct linting (spaces, single quotes, etc.).

[dreamorosi]

Super, thanks for kicking off this part of the documentation :)

[saragerion]

This feature will be super useful, thanks for adding it. Added a minor comment.

[dreamorosi]

Let's merge it!

[saragerion]