✨ Support for <fieldset> and <legend> tags

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**Is your feature request related to a problem? Please describe.**
According to GeeksForGeeks: The tag in HTML5 is used to make a group of related elements in the form. This tag is a new addition in HTML5, serving as a container for grouping form elements. The [ tag](https://www.geeksforgeeks.org/html-legend-tag/#:~:text=The%20legend%20tag%20is%20used,for%20the%20element.) is used to define the title for the child’s contents.

There is currently no styling for fieldset tags in chimera, and adding it would give the developer more flexibility when using Chimera.

**Describe the solution you'd like**
Implement styling for fieldset and legend tags, that is consistent with our design philosophy. It should also look good across all themes

**Additional context**
Under the section for unimplemented elements at chimera demo page, the tags are implemented. It could be useful to use this page as a reference when changing the element to ensure consistency with the rest of the design.

Start with the Chimera demo page's unimplemented-elements section and inspect how nearby HTML elements are styled across the available themes. Identify the SCSS styles for related form elements, then add consistent fieldset and legend presentation and verify both tags look appropriate in every theme.

Written by the indexing model from the issue text.