eoc: move non-board docs from boards TOC list

A couple of docs were created in previous PRs with board support
information common to a few boards.  Move these to a new section
for "Board Support Tools".  (I debated about hiding them completely
but decided it would still be useful to have these tool docs appear
in the table of contents, just not embedded with the supported boards
docs.)

Moved these board tools docs over to the doc/ folder and out of
boards/ and removed these pages from the navigation index.

JIRA: ZEP-2285

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