Plugin request: Add some general SEO optimizations

## Summary
Some meta tags are pretty typical nowadays for SEO optimization and could easily be auto-generated.

### Basic example
```js
export default {
metaInfo: { title: "My super SEO optimized page" }
}
```
could automatically add meta tags for `twitter:title`, `og:title`, etc. Same for "description".

Another example would be the canonical URL:
`` which would be easy to generate using the current route.

### Motivation
SEO optimization is important for many and at least useful for almost everyone else. It is also not hurting anyone to have it.