feat: update project creation

[lorenzo-cavazzi]

This PR updates the project and group creation pages, which are now available as modals.
The settings pages have been updated accordingly, but they will undergo further updates in another pitch.

Reference: https://www.notion.so/renku/Clean-up-Project-Group-Creation-0bee33f12b624525a100df79327eb5e7

/deploy renku=release-0.62.0

[RenkuBot]

You can access the deployment of this PR at https://renku-ci-ui-3399.dev.renku.ch

[leafty]

Some more comments here 👇 .

The PR is overall good, but form code needs to be improved.

[lorenzo-cavazzi]

@leafty thank you for the review!

I either updated the code as suggested or dropped an inline content. Most points are solved or trivial to solve after a confirmation (E.G: Group vs GroupV2).
The one outstanding is "how to treat routes" / "where to put modals". I'm happy to talk about it offline to explain the requirements better and understand your proposed solution.

[andre-code]

If needed, the copy for error messages should be checked with a native English speaker from the product team.

Thanks @leafty, copy approved by Product team

[RenkuBot]

Tearing down the temporary RenkuLab deplyoment for this PR.