Add migration to migrate-v2 script for `QwikCityMockProvider`, `QwikCityMockProps`, `opts?.serverData?.qwikcity`

[maiieul]

Those were missing and I had to manually update them. The serverData.qwikcity one wasn't obvious to find.

[thejackshelton]

Look at the migration guide I created @wmertens looked that one over.

Also migration guide should convert any:

@qwikdev/astro to @qwik.dev/astro

[thejackshelton]

I would like to rename pnpm qwik migrate-v2 -> pnpm qwik upgrade, and make it an upgrade script that people remember similar to Astro