web: provide storybook demos and docs for existing tests (#11651)

* Added tests and refinements as tests indicate.

* Building out the test suite.

* web: test the simple things. Fix what the tests revealed.

- Move `EmptyState.test.ts` into the `./tests` folder.
- Provide unit tests for:
  - Alert
  - Divider
  - Expand
  - Label
  - LoadingOverlay
- Give all tested items an Interface and a functional variant for rendering
- Give Label an alternative syntax for declaring alert levels
- Remove the slot name in LoadingOverlay
  - Change the slot call in `./enterprise/rac/index.ts` to not need the slot name as well
- Change the attribute names `topMost`, `textOpen`, and `textClosed` to `topmost`, `text-open`, and
  `text-closed`, respectively.
  - Change locations in the code where those are used to correspond

** Why interfaces: **

Provides another check on the input/output boundaries of our elements, gives Storybook and
WebdriverIO another validation to check, and guarantees any rendering functions cannot be passed
invalid property names.

** Why functions for rendering: **

Providing functions for rendering gets us one step closer to dynamically defining our forms-in-code
at runtime without losing any type safety.

** Why rename the attributes: **

A *very* subtle bug:
[Element:setAttribute()](https://developer.mozilla.org/en-US/docs/Web/API/Element/setAttribute)
automatically "converts an attribute name to all lower-case when called on an HTML element in an
HTML document." The three attributes renamed are all treated *as* attributes, either classic boolean
or stringly-typed attributes, and attempting to manipulate them with `setAttribute()` will fail.

All of these attributes are presentational; none of them end up in a transaction with the back-end,
so kebab-to-camel conversions are not a concern.

Also, ["topmost" is one word](https://www.merriam-webster.com/dictionary/topmost).

** Why remove the slot name: **

Because there was only one slot.  A name is not needed.

* Fix minor spelling error.

* First pass at a custom, styled input object.

* .

* web: Demo the simple things. Fix things the Demo says need fixing.

- Move the Element's stories into a `./stories` folder
- Provide stories for (these are the same ones "provided tests for" in the [previous
  PR](https://github.com/goauthentik/authentik/pull/11633))
  - Alert
  - Divider
  - Expand
  - Label
  - LoadingOverlay
- Provide Storybook documentation for:
  - AppIcon
  - ActionButton
  - AggregateCard
  - AggregatePromiseCard
  - QuickActionsCard
  - Alert
  - Divider
  - EmptyState
  - Expand
  - Label
  - LoadingOverlay
  - ApplicationEmptyState
- Fix a bug in LoadingOverlay; naming error in nested slots caused any message attached to the
  overlay to not sow up correctly.
- Revise AppIcon to be independent of authentik; it just cares if the data has a name or an icon
  reference, it does not need to know about `Application` objects. As such, it's an *element*, not a
  *component*, and I've moved it into the right location, and updated the few places it is used to
  match.

* Prettier has opinions with which I sometimes diverge.

* Found a bug! Although pf-m-xl was defined as a legal size, there was no code to handle drawing something XL!

* Found a few typos and incorrect API descriptions.

web/src/elements/stories/LoadingOverlay.stories.ts

@@ -0,0 +1,74 @@
+import type { Meta, StoryObj } from "@storybook/web-components";
+
+import { LitElement, TemplateResult, css, html } from "lit";
+import { customElement, property } from "lit/decorators.js";
+
+import { type ILoadingOverlay, LoadingOverlay } from "../LoadingOverlay.js";
+import "../LoadingOverlay.js";
+
+const metadata: Meta<LoadingOverlay> = {
+    title: "Elements/<ak-loading-overlay>",
+    component: "ak-loading-overlay",
+    parameters: {
+        docs: {
+            description: "Our empty state spinner",
+        },
+    },
+    argTypes: {
+        topmost: { control: "boolean" },
+        // @ts-ignore
+        message: { control: "text" },
+    },
+};
+
+export default metadata;
+
+@customElement("ak-storybook-demo-container")
+export class Container extends LitElement {
+    static get styles() {
+        return css`
+            :host {
+                display: block;
+                position: relative;
+                height: 25vh;
+                width: 75vw;
+            }
+            #main-container {
+                position: relative;
+                width: 100%;
+                height: 100%;
+            }
+        `;
+    }
+
+    @property({ type: Object, attribute: false })
+    content!: TemplateResult;
+
+    render() {
+        return html` <div id="main-container">${this.content}</div>`;
+    }
+}
+
+export const DefaultStory: StoryObj = {
+    args: {
+        topmost: undefined,
+        // @ts-ignore
+        message: undefined,
+    },
+
+    // @ts-ignore
+    render: ({ topmost, message }: ILoadingOverlay) => {
+        message = typeof message === "string" ? html`<span>${message}</span>` : message;
+        const content = html` <ak-loading-overlay ?topmost=${topmost}
+            >${message ?? ""}
+        </ak-loading-overlay>`;
+        return html`<ak-storybook-demo-container
+            .content=${content}
+        ></ak-storybook-demo-container>`;
+    },
+};
+
+export const WithAMessage: StoryObj = {
+    ...DefaultStory,
+    args: { ...DefaultStory.args, message: html`<p>Overlay with a message</p>` },
+};