Optimize stylesheets by minifying CSS

### Description
Currently, it seems the extensions CSS stylesheet `index.css` is not minified and contains unnecessary whitespace, comments, and redundant code that can affect the performance of the platform. By minifying the CSS files, we can significantly reduce their file size and improve the loading time for the extension. This issue proposes implementing a minification process for the CSS files used in GitHub to optimize the platform's stylesheets.

Currently the stylesheet for the extension is `4.8mb` after running some quick experiments we should be able to get that down to ~`1.5mb`


### Technical Details
- Add minification process to the build system for the extension

### Acceptance Criteria
- Size of stylesheets have greatly reduced
- Low impact on the build time of the extension
- No visual degradation due to minification process