feat: add rendered hook

[svewag]

This rendered hook can be used e.g. in order to set some dynamic http header depending on your vue app.

[svewag]

Hi!

Is there any chance that this will finde the way into a next release?
That would be awesome, especially for our current project which is under development 😄

Btw. #77 is another great feature for customization

[Akryum]

👍