feat(devx): introduce storybook

First shot at introducing storybook, with stories for the keycloak
theme pages already in the repo.

src/keycloak-theme/pages/Register.stories.tsx

@@ -0,0 +1,69 @@
+import { ComponentMeta } from '@storybook/react';
+import KcApp from '../KcApp';
+
+import { useKcStoryData, socialProviders } from '../../../.storybook/data'
+
+export default {
+  title: 'Register',
+  component: KcApp,
+  parameters: {
+    layout: 'fullscreen',
+  },
+} as ComponentMeta<typeof KcApp>;
+
+const pageId = 'register.ftl'
+
+export const Default = () => {
+  const { kcContext } = useKcStoryData({ pageId, message: undefined })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const InFrench = () => {
+  const { kcContext } = useKcStoryData({ pageId, message: undefined, locale: { currentLanguageTag: 'fr' } })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const WithError = () => {
+  const { kcContext } = useKcStoryData({ pageId, message: { type: "error", summary: "This is an error" } })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const EmailIsUsername = () => {
+  const { kcContext } = useKcStoryData({
+    pageId, message: undefined,
+    realm: { registrationEmailAsUsername: true }
+  })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const NoPassword = () => {
+  const { kcContext } = useKcStoryData({
+    pageId, message: undefined, passwordRequired: false
+  })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const WithRecaptcha = () => {
+  const { kcContext } = useKcStoryData({
+    pageId, message: undefined,
+    recaptchaRequired: true,
+    recaptchaSiteKey: 'foobar'
+  })
+  return <KcApp kcContext={kcContext} />
+}
+
+export const WithPresets = () => {
+  const { kcContext } = useKcStoryData({
+    pageId, message: undefined,
+    register: {
+      formData: {
+        firstName: 'Max',
+        lastName: 'Mustermann',
+        email: 'max.mustermann@mail.com',
+        username: 'max.mustermann'
+      }
+    }
+  })
+  return <KcApp kcContext={kcContext} />
+
+}