refactor: standardize create-vite vanilla templates

[n-ce]

Description

• Includes removal of innerHTML which is not considered a safe practice, replaces it with textContent.
• Reduces usage of javascript / typescript to add to DOM, instead relies on standard HTML.
• Replaces div#app with standard main tag
• As a side effect there might be a slight increase in performance, but that is not the goal here.

Additional context

This PR is meant to be squash merged

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines, especially the Pull Request Guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Update the corresponding documentation if needed.
• Ideally, include relevant tests that fail without this PR but pass with it.

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[bluwy]

I'm not sure if we need this change. The code is meant to mimic how the other framework templates like React and Vue renders things. This makes it less consistent with the other templates.

[sapphi-red]

I agree with bluwy, let's keep the templates as-is. But thanks for the PR anyways.