Post 2.0 updates for wiki website

From website/wiki:

• The release plan of 2.0 should be removed, especially the menton of postgres support;
• The website should have a more prominent link to the wiki 2.0 space;
• The wiki home page provides no prominent / or perhaps even no reference to the 2.0
  documentation at https://wiki.opendnssec.org/display/OpenDNSSEC/OpenDNSSEC+Project+Wiki+Homepage.
• the link to the https://wiki.opendnssec.org/display/DOCS20/Quick+start+guide in
  the 2.0.0 release message on the website is not clickable.