Previously, we were using the example's Makefile to configure whether we want a web server built into the BR. We had 3 options:
* No web server
* Internal web server
* External web server (from apps/)
The last option is no longer evailable. This commit removes support for this option and it also simplifies the situation: We now merely use a CPP macro to enable/disable the web server.
This example used to be considered specific to the CC2538DK platform. However, there was nothing really platform-specific to it. This commit moves the example to the top-level examples directory and documents it.
