refactor(type): Move Button style edge case to theme

The combination of `outline={true}` and `color="gray"`
triggers a set of special classes. So I set up the
API like so:

```js
outline: {
  base: '..',
  color: {
    gray: 'special case classes',
    ... any other special cases the user may need to accomodate
  },
  ..
}
```

src/lib/components/Button/Button.spec.tsx

@@ -90,7 +90,13 @@ describe('Components / Button', () => {
 
   describe('Rendering', () => {
     it('should render', () => {
-      const button = getButton(render(<Button>Hi there</Button>));
+      const button = getButton(
+        render(
+          <Button color="gray" outline>
+            Hi there
+          </Button>,
+        ),
+      );
 
       expect(button).toHaveTextContent('Hi there');
     });

src/lib/components/Button/index.tsx

@@ -58,12 +58,12 @@ const ButtonComponent: FC<ButtonComponentProps> = ({
   return (
     <button
       className={classNames(
-        color === 'gray' && outline && 'border border-gray-900 dark:border-white',
         disabled && theme.disabled,
         !gradientDuoTone && !gradientMonochrome && theme.color[color],
         gradientDuoTone && !gradientMonochrome && theme.gradientDuoTone[gradientDuoTone],
         !gradientDuoTone && gradientMonochrome && theme.gradient[gradientMonochrome],
         groupTheme.position[positionInGroup],
+        outline && theme.outline.color[color],
         theme.base,
         theme.pill[pill ? 'on' : 'off'],
       )}

src/lib/components/Flowbite/FlowbiteTheme.d.ts

@@ -1,6 +1,6 @@
 import type { AlertColors } from '../Alert';
 import type { AvatarSizes } from '../Avatar';
-import { ButtonColors, ButtonOutlineColors, ButtonSizes, PositionInButtonGroup } from '../Button';
+import { ButtonColors, ButtonSizes, PositionInButtonGroup } from '../Button';
 import { ButtonGradientColors, ButtonGradientDuoToneColors } from '../Button';
 
 export type CustomFlowbiteTheme = DeepPartial<FlowbiteTheme>;

src/lib/theme/default.ts

@@ -183,6 +183,9 @@ export default {
     label:
       'ml-2 inline-flex h-4 w-4 items-center justify-center rounded-full bg-blue-200 text-xs font-semibold text-blue-800',
     outline: {
+      color: {
+        gray: 'border border-gray-900 dark:border-white',
+      },
       off: '',
       on: 'bg-white text-gray-900 transition-all duration-75 ease-in group-hover:bg-opacity-0 group-hover:text-inherit dark:bg-gray-900 dark:text-white',
       pill: {