* Migrate off go-bindata to embed built-in fonts, levels and doodads in
favor of Go 1.16 native embed functionality.
* `make bindata` prints a deprecation warning to not break older build
scripts
* Removes all references of bindata from the program
* Tightens up the surface area of API methods available to the
JavaScript VMs for doodads. Variables and functions are carefully
passed in one-by-one so the doodad script can only access intended
functions and not snoop on undocumented APIs.
* Wrote tons of user documentation for Doodad Scripts: documented the
full surface area of the exposed JavaScript API now that the surface
area is known and limited.
* Early WIP code for the Campaign JSON
