Improve typings and update dependencies

[eoinsha]

Description

• Improve typings to avoid any usages
• Define a metric registry to get consistency between dashboard and alarm metrics
• Update dependencies for security and compatibility with Serverless Framework v4

Motivation and Context

• Security audit response
• Compatibility with supported serverless framework

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING.md document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[coveralls]

coverage: 97.404% (-0.3%) from 97.662% — hygiene-update into main