feat: added rendered func to ssrContext

[hagushorn]

Maintain compatibility with some well-known Vue plugins, like @vue/apollo-ssr

[pi0]

Thanks for the pull request @hagushorn! I'm fine with adding this hook but would you please elaborate more about "maintain compatibility" ? Do you need it for Nuxt or custom vue ssr?

[hagushorn]

Thanks for the pull request @hagushorn! I'm fine with adding this hook but would you please elaborate more about "maintain compatibility" ? Do you need it for Nuxt or custom vue ssr?

Hello! I'm so sorry for the long reply :(
For the most part this is for a custom vue ssr. But i think in the nuxt with vue apollo library will need it too