Make use of the resource bundle optional

[paulcadman]

The goal of this PR is to allow configuration of the project for loadImage path (and future APIs that load resources) to load resources from the filesystem instead of the resource bundle.h.

This is done in multiple steps.

1. The makeBundle.lean script now creates resources in bundle.h with path prefixed with resource/, i.e their relative paths in the repository. So now in the Window example the image is loaded using loadImage "resources/Asset.svg" instead of loadImage "Asset.svg".

2. A C-flag RAYLEAN_NO_BUNDLE is added so that raylib-binding.c can be configured to use the Raylib LoadFileData instead of loading data from the bundle. The loadImage "resources/Asset.svg" will continue to work when the example executable is run from the root of the project (i.e with just run).

3. A config option bundle is now used in the lakefile to configure if the bundle is used or not.

Builds using just will continue to use the resource bundle by default.

To disable use of the bundle in just use:

just disableBundle=y build

Projects that depend on the raylean library will have the bundle disabled by default. It can be enabled by setting the bundle configuration setting to on in the lakefile requires block:

require raylean from git "https://github.com/paulcadman/raylean" @ "main" with
  NameMap.empty
    |>.insert `bundle "on"

or via the CLI:

lake build -R -K bundle=on build