Add support for project directories to be opened where browsers support it.

[davetcc]

Chrome and Edge both support the concept of opening a directory of files to read from the browser. This ticket is to be able to use TcMenu web designer in the same mode as it used to work on desktop.

Steps:

1. the user opens a directory by choosing it
2. the existing menu tree and options are loaded
3. when generate is triggered, all required content is sent to the server, this will include the i18n directory and the sketch.
4. the server will generate the code adjusting the users files.
5. the web client examines the response and patches the files in place, exactly as existing designer used to do.