docs: add documentation on how to build rollups on Celestia with blobstream

.vitepress/config.ts

@@ -630,6 +630,10 @@ function sidebarHome() {
                 },
               ],
             },
+            {
+              text: "Blobstream rollups",
+              link: "/developers/blobstream-rollups",
+            },
             {
               text: "Other",
               collapsed: true,