Move RepoItemLinkGenerator into client namespace

Change-Id: I2afeda32852f1f7f2f2bb0c294b4617679044d63
(cherry picked from commit 7161c7602dfbc6d337f0c4df4d201cb4271ebf90)
Move EntityPerPage-related classes into namespaces

Change-Id: Idd5096880f6c3ceab2cdb7b7edc734bf00689f4b
(cherry picked from commit eb4dffd77b51c287f68c35d5574a3193a0d2b9e1)
Merge "Move EntityPerPage-related classes into namespaces" into wmf/1.25wmf1