[FEAT][TABLE] Add option to unstyle table component

[KevinFabre-ods]

⚠️ This PR introduces SASS support in the style tag. To have scss highlighted in VSCODE follow instruction in this article https://daveceddia.com/svelte-with-sass-in-vscode/

Summary

The goal for this PR is to add an unstyled props to reset all presentation style.

(Internal for Opendatasoft only) Associated Shortcut ticket: sc-46255.

Changes

• Place all table presentation styles behind the ods-dataviz-sdk-table--default class
• Add the scss language to easily style Table components.
• Also update eslint plugin svelte3 to prevent lint error when using scss in a style tag. https://github.com/sveltejs/eslint-plugin-svelte3/blob/master/CHANGELOG.md#330
• Update the table theme utils to not alter the DEFAULT_THEME object.

To be tested

• Snapshots shouldn't changes.

Review checklist

• Description is complete
• Commits respect the Conventional Commits Specification
• 2 reviewers (1 if trivial)
• Tests coverage has improved
• Code is ready for a release on NPM

[KevinFabre-ods]

@etienneburdet I updated a bit the styling here 4d9ce81

I removed the CSS variables.
Now Table components has scoped classnames on their HTML elements, this leads to a simple style override.

[etienneburdet]

Works as intended, ok for me to ship that. As with the formatting one, global and scss nesting doesn't really play together, but well… there is no great solution to that.