Navigate-to-Site-Page APIs

When IPF Installed Site Pages are migrated from IPF 3.1 to IPF 4.x, the /IPFSitePages/ folder is added for all site page content. Existing scripting that was using NavigateToSitePage and NavigateToSitePageAsURL APIs continues to work without manual changes, because the APIs only pass in a page name and expect to find the pages all in the same folder.