Implement new design for Welcome page (#33211)

* Convert welcome.html to React component

In advance of changes to use Compound

* Fix types

* Fix tests

* Update styling to match Figma

* Fix random capitalisation

* Tweak styling

* Regenerate i18n

* Update tests

* Make linter happy

* Iterate

apps/web/playwright/e2e/app-loading/guest-registration.spec.ts

@@ -20,7 +20,7 @@ test.use({
 
 test("Shows the welcome page by default", async ({ page }) => {
     await page.goto("/");
-    await expect(page.getByRole("heading", { name: "Welcome to Element!" })).toBeVisible();
+    await expect(page.getByRole("heading", { name: "Be in your element" })).toBeVisible();
     await expect(page.getByRole("link", { name: "Sign in" })).toBeVisible();
 });
 

apps/web/playwright/e2e/login/login-consent.spec.ts

@@ -126,7 +126,7 @@ test.describe("Login", () => {
             await page.goto("/");
 
             // Should give us the welcome page initially
-            await expect(page.getByRole("heading", { name: "Welcome to Element!" })).toBeVisible();
+            await expect(page.getByRole("heading", { name: "Be in your element" })).toBeVisible();
 
             // Start the login process
             await expect(axe).toHaveNoViolations();