refactor internal package for importing code as lib

[jordipainan]

Summary by CodeRabbit

• Refactor: Updated import paths across the codebase to use new helpers and metrics packages, improving modularity and maintainability.
• Refactor: Changed the import path for the lexer package in the strategyoperators module, enhancing code consistency.
• Refactor: Renamed the internal package to metrics, providing a more descriptive name that better reflects its functionality.

[github-actions[bot]]

CodeRabbit

Walkthrough

This change set primarily focuses on refactoring the import paths across the codebase. The internal package has been split into helpers and metrics packages, and all references have been updated accordingly. This includes changes for lexer, strategyoperators, and queue.

Changes

Files	Summary
api/api.go, api/censuses.go, api/helpers.go, api/strategies.go, api/tokens.go	Refactored the import paths to use new packages for metrics and rounded census helpers. Updated references from the internal package to the helpers and metrics packages.
helpers/strategyoperators/operators.go, helpers/strategyoperators/operators_test.go, helpers/strategyoperators/strategyoperators.go	Changed the import path for the lexer package from github.com/vocdoni/census3/internal/lexer to github.com/vocdoni/census3/helpers/lexer.
metrics/metrics.go	Changed package name from internal to metrics.

🐇

In the land of code where the shadows lie,

We refactor, we update, under the cloudless sky.

From internal to helpers, then metrics we go,

Making our codebase a more organized show.

With each pull request, a new dawn begins,

Celebrating changes, that's how everyone wins! 🎉

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