net: tests: Enables all net kconfig options in one test case

This creates a test case that enables all the currently known
network related Kconfig options. This is useful so that we can
compile test various Kconfig options. Note that the result binary
is not meant to be run anywhere and it will probably not run as
some of the enabled options do not make sense in real life.

Change-Id: Iede36131b43d95acb78b4094004626e1b86e0f95
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>