doc: fix title generation for config options pages

Use the ReST metadata document title directive instead of
embedded javascript to assign a title to the configuration
options (Kconfig) reference guide pages.  This will generate
a static <title> directive in the generated HTML instead
of relying on javascript.

Change-Id: Ib70a8b1f641a5ed72be774f0f5b2a93a2d1c9b8c
Signed-off-by: David B. Kinder <david.b.kinder@intel.com>