feat(qwik-nx): nx 21 support

[harrywebdev]

What is it?

• Feature / enhancement
• Bug
• Docs / tests

Description

1. Migrate this Nx monorepo to latest Nx v21.
2. Update qwik-nx peerDependencies to require version ^21.0.0 of @nx packages

Use cases and why

• 1. Use case: use Nx v21

Screenshots/Demo

N/A

Checklist:

• My code follows the developer guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• Added new tests to cover the fix / functionality

[harrywebdev]

This PR is somewhat incomplete - I assume a major/minor bump in the qwik-nx package is preferable (together with README change), which I haven't done. Also, maybe maintainers also want/need to perform other version bumps, so I'd like this PR to be considered as a starting point 🙏🏻 Let me know, if there's anything else I can do.

[dmitry-stepanenko]

Hey @harrywebdev thanks for the effort! I will take it from here

[dmitry-stepanenko]

the work has been done in another PR #251