We only want to allow specific things from the main world to be
exposed to the render process, thus this patch adds a preload script
which allows exposing specific functionalities to the render process.
Also add locale as a valid channel. This patch also adds preload.js to
electron build.
This patch also disables node integration because enabling
nodeIntegration that allows outsiders to run any node script which can
be a security issue, we should use contextIsolation to provide what all
methods we want to expose from the main World.