[CDF-26176] interactive init (#2172)

# Description

The `cdf init` was a missed opportunity to onboard users. Let's provide
an interactive experience in v0.7!


https://github.com/user-attachments/assets/b5c6da54-57b2-487f-a55e-1ddd65d9cd95

How to test: 

in a fresh directory, run 

```
pip install --upgrade git+https://github.com/cognitedata/toolkit.git@better-init
cdf init --seven 
```

(`--seven ` is a hidden flag to enable the feature since we don't have a
cdf.toml to get flags from at this stage)

## Changelog

- [x] Patch
- [ ] Skip

## cdf

### Improved

- Interactive onboarding in cdf init

## templates

No changes.

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Anders Albert <60234212+doctrino@users.noreply.github.com>
