OAK-301: Document Oak
Remove links to Wiki or declare as of historical interest otherwise

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1595932 13f79535-47bb-0310-9956-ffa450edef68
OAK-301 : oak docu

Adding details related to various BlobStore implementations

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1595935 13f79535-47bb-0310-9956-ffa450edef68