Adds semantic colors and base styles for form elements

[stephiescastle]

Checklist

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Description

Fixes #42:

• Updates @tailwindcss/forms to v0.3.4
• Adds all semantic colors to branding guidelines
• Adds /src/scss/_forms.scss as base styles for form elements.
• Adds a few Forms stories to illustrate the updated styles
• Updates explorer-1.min.css

Breaking changes

• Input fields will now default to having a gray-light-mid border. For input fields that should not have a border, add class border-0 to them.
• Projects importing SCSS partials a la carte will need to import the new _forms.scss partial as one of the first imports in the main SCSS file.
• Projects that have defined their own semantic colors should remove those color definitions from their TailwindCSS config and use those provided by Explorer-1 instead.

Instructions to test

1. npm run storybook
2. Check the stories under Components/Forms to see these styles in action.
3. Check the Colors story to see all semantic colors added.

Tested in the following environments/browsers:

Operating System

• macOS
• iOS
• iPadOS
• Windows

Browser

• Chrome
• Firefox ESR
• Firefox
• Safari
• Edge

[Scotchester]

Checks out!

I'm going to remove the storybook label so that it doesn't appear in the Docs section of the release notes. I think I need to turn off the autolabeling of storybook when files with that in the path are edited. We really only want a PR in that section of the change log if it's primary purpose is a significant addition or update to Storybook.