Add Gerrit training for doc reviewers to the
resources folder.
Add index-resources file.
Add training PDF and link on Contribution page.
Trying reference directive.
Removed changes on Contribution page for now.
Change-Id: I2b1526c1d03e4ccb20d53331a1d6586aad7ead63
Signed-off-by: MCamp859 <maryx.camp@intel.com>