Multiple themes support

[ksiabani]

Matte should be able to support multiple themes. Theming in Matte exists in two levels:

Theme selection

The user should be able to select amongst multiple themes. This includes element styling that is specific to the design system, e.g. the padding and line-height of the button. For this, the user could tweak an object containing the properties.

Theme customisation

The user should be able to further customise the selected theme. This inludes design aspects that can be customised through MUI theming , like colors and fonts. For this, maybe we could use multiple [name].[themeName].module.scss files.

Themes should be also selectable from within the storybook.