feat(useTitle): useTitle composable

[pikax]

relates #317

Returns title ref, it will be kept up to date with the current header, it relies on MutationObserver to keep header updated 97.5%

const title = useTitle(defaultTiltle);

title.value = 'update title'

Example

Also added SSR support for v3:

const app = createSSRApp(Comp);
const title = provideSSRTitle(app, 'my title') // send app to the method
const htmlContent = await app.renderToString(el)
// title has the last title set