Enhance json schema (#353)

* feat: provide intellisence for configs

* feat: more constrains and hints

Provide:
- examples
- better descriptions
- url to repo

Disallow:
- space only strings

* fix: add missing titles

* fix: help keys

Use 'Not provided' placeholder

* Revert "fix: help keys"

This reverts commit 2a939cf8aeb7d105fe989328034b367ddb93bf25.

* fix: don't use strict JSON schema validation

* Revert "fix: don't use strict JSON schema validation"

This reverts commit 61d50085fb09bf00601b036fa433dc279d53668b.

* fix: specify `type` for definition