Json schema generator (#53)

* add json schema generator

* add props & targets, cli tool

* fix incorrect type check in attribute factory
implement enum hints

* update pipeline

* undo namespace cleanup

* fix formatting

* move from InternalsVisibleTo to public types

* clean test app

* do not delete schemata dir in cli tool

* set tfm for publish project reference target to net9

* remove obsolete test app

* add readme

* add logo

Author: SleepWellPupper