Allow for multiple templates to be saved rather than just the last one

[schreiaj]

Pull Request

Description

Previously adding a new template would overwrite all existing ones in the localStorage DB, this change persists those in addition to the new one.

Related Issues

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Additional Notes

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Checklist

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• [ ] I have ensured that the pull request is of a manageable size, allowing it to be reviewed within a single session.
• [ ] I have reviewed my changes to ensure they are clear, concise, and well-documented.
• [ ] I have updated the documentation, if applicable.
• [ ] I have added or updated test cases to cover my changes, if applicable.
• [ ] I have minimized the number of reviewers to include only those essential for the review.
• [ ] I have notified teammates in the review thread to build awareness.

Checklist for Reviewers

Please review and complete the following checklist during the review process:

• [ ] The code follows best practices and conventions.
• [ ] The changes implement the desired functionality or fix the reported issue.
• [ ] The tests cover the new changes and pass successfully.
• [ ] Any potential edge cases or error scenarios have been considered.