This PR brings the build output of PCUI Graph in line with the PCUI library.
Exports umd and module builds which contain the pcui and playcanvas observer libs as external dependencies. The UMD build looks for these in the global namespace. The module build imports these libs instead.
Included a build that creates the libraries type def file.
Declared the main, module, types and files properties in the package.json which allows us to build a standard npm package.
Updated the readme
Tested in the shader editor and main PlayCanvas editor
This PR brings the build output of PCUI Graph in line with the PCUI library.
Tested in the shader editor and main PlayCanvas editor