add openssl doc

.vitepress/Ecosystem.mts

@@ -22,4 +22,11 @@ export const EcosystemSideBar: DefaultTheme.SidebarItem[] = [
             {text: 'init', link: "/ecosystem/binding/init"},
         ]
     },
+    {
+        text: 'Third-Party',
+        collapsed: false,
+        items: [
+            {text: 'OpenSSL', link: "/ecosystem/third/openssl"}
+        ]
+    }
 ];

src/ecosystem/third/openssl.md

@@ -0,0 +1,17 @@
+---
+editLink: true
+---
+
+# OpenSSL
+
+In OpenHarmony, the official does not provide out-of-the-box openssl capabilities, but this library exists as the basic capability of a large number of other basic capabilities. Therefore, we need to build the openssl library that can run on OpenHarmony ourselves. We provide basic pre-built products, supporting the following platforms.
+
+- arm64-v8a
+- armeabi-v7a
+- x86_64
+
+We provide some simple usage examples, which are based on the `reqwest` package. You can find them in the code [here](https://github.com/ohos-rs/example/tree/main/example/reqwest).
+
+## Source Code
+
+You can find the pre-built products [here](https://github.com/ohos-rs/ohos-openssl).