Update the new contribute link at the footer
Update the new contribute link at the footer

Now the link for Contribute at the footer is changed from wiki
to infra-manual link

Change-Id: I0571ad547ba338398cb0859118fd03a084e17215

Tesora/tesora-api-site,Tesora/tesora-api-site,openstack/api-site,Tesora/tesora-api-site,openstack/api-site,openstack/api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,openstack/api-site,Tesora/tesora-api-site