Remove keybindings

[pykong]

The project_maker is supposedly not run very frequently due to its very nature.
This alleviates the need for a keybinding.
Additionally the currently defined keybinding ctrl + shift + n shadow the inbuilt command for creating a new window.

Hence, I suggest to remove the inbuilt keymap files.
As a replacement a short info on how to create a custom keybinding for project_maker could be added to the documentation. A configuration any ST user is able to perform.