docs: updates and final fixes

docs: updates and final fixes

Migrate the installation guide for vsperf to a configguide directory,
update the links to the installation guide. Re-add top level index.rst
and remove the all directory. Update release documentation with vsperf
Rel B support.

Change-Id: Ib643b9d3581d8109b85c377027c8cc6be4b797fc
Signed-off-by: Maryam Tahhan <maryam.tahhan@intel.com>
Reviewed-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Radek Zetik <radekx.zetik@intel.com>
Reviewed-by: Dino Simeon Madarang <dino.simeonx.madarang@intel.com>
Reviewed-by: Brian Castelli <brian.castelli@spirent.com>