…rved in esbuild dev server

Previously when using the esbuild-based browser application builder with the new dev server,
resource files referenced via stylesheets may not have been served by the development server.
The development server has now been adjusted to properly prioritize and serve files that were
generated during the build process.
Global stylesheets are also currently considered resource files as well to workaround issues
with development sourcemaps within the development server itself. Global stylesheets are already
fully processed by the build system prior to being passed to the development server.

…output to relative path

The output option for the long-form of the assets build option should be a relative path based
from the output path of the application. However, a rooted path was also considered relative
to the output path. To avoid two different ways of representing the path throughout the build
system. The output path is now normalized to a relative path at the beginning of the build
process.