[DOC] Add a link to index

New documentation generation system relies on disjoint documentations.
This patch adds an label for OOM main index with name being consistent
accross all ONAP components.

Issue-ID: CIMAN-376
Change-Id: I1c13b2c478857c45a30ec5e5fb4881934e6f70f3
Signed-off-by: lf-jobbuilder <releng+lf-jobbuilder@linuxfoundation.org>
Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>
1 file changed