Feat: graphical doctypes access

Currently, it requires a lot of manual work and also some low code experience to access frappe doctypes within builder.
While https://frappeframework.com/docs/user/en/desk/scripting/script-api provides a good overview about how to access data from doctypes I would prefer to see a no code option in the future.

So fetching available doctypes, and also filtering necessary data in a pure graphical way. A folder like structure with a search option could be a possible implementation.