PR for Milestone 1: Adding the page-color-scheme

[tingting-lwy]

PR for Milestone 1: Adding the page-color-scheme

• Added a property data-theme-color that can take either manifold-scheme-light or manifold-scheme-dark
• Included the Scheme utility classes .manifold-scheme-dark and .manifold-scheme-light
• Used window.matchMedia to query for user's browser OS preference (if set to dark, will choose manifold-scheme-dark, if light then manifold-scheme-light)
• Provided input as a dropdown selector to choose the theme on the configurator UI
• Added the configuration option of page color scheme to Restricted Token and Wallet Identity Widgets too, but not sure if that is necessary as those widgets aren't displayed

An example of the dark theme:

An example of the light theme

[jaxonL]

linking first pass review for reference tingting-lwy#1 (review)

[jaxonL]

looks good to me! if anything needs improvement, it would be putting the widgetTheme options as a default for any widget, so we wouldn't need to redefine the prop in each newly added widget config. for now, this is sufficient.

[jaxonL]

this works -- was thinking since we have set values for the theme stuff (the scheme utility classes), we can be more explicit about what a theme is.