feat(page): add custom page library support (css and js) (#357)

exampleSite/content/posts/theme-documentation-basics/index.en.md

@@ -551,6 +551,18 @@ Please open the code block below to view the complete sample configuration :(far
         label = ""
         lightTheme = "github-light"
         darkTheme = "github-dark"
+    # {{< version 0.2.7 >}} Third-party library config
+    [params.page.library]
+      [params.page.library.css]
+        # someCSS = "some.css"
+        # located in "assets/"
+        # Or
+        # someCSS = "https://cdn.example.com/some.css"
+      [params.page.library.js]
+        # someJavascript = "some.js"
+        # located in "assets/"
+        # Or
+        # someJavascript = "https://cdn.example.com/some.js"
     # {{< version 0.2.0 >}} SEO config
     [params.page.seo]
       # Publisher info