Fix links on "Participate" Menu

Please change these links the 'Participate Menu':

• ArchivesSpace Hosting -> https://sites.google.com/view/dlg-docs/resources/programs-and-projects/archivesspace-hosting-pilot
• Subgranting Program -> https://sites.google.com/view/dlg-docs/resources/programs-and-projects/subgranting-program
• Documentation and Reports -> https://sites.google.com/view/dlg-docs/
• Presentation and Workshops -> https://sites.google.com/view/dlg-docs/
• Promotional Materials -> https://sites.google.com/view/dlg-docs/