docs: Add auto-generated type declarations

[Techassi]

Create a custom plugin which accepts the raw Markdown content and replaces

```dts
<SYNTAX>
```

with auto-generated content. The exact replacement content needs to be explored. One possibility is to inject raw Markdown content again, which Vitepress can then render into HTML. The generated content could look like this:

::: details Show Type Declarations
```ts
<TYPESCRIPT_DECLARATIONS>
```
:::

This feature will most likely require the migration of this repo into the https://github.com/vue-youtube/vue-youtube repo. This migration enables us to have direct access to the raw TS files and delaration files.