codesign: add page (#1523)

pages/osx/codesign.md

@@ -0,0 +1,11 @@
+# codesign
+
+> Create and manipulate code signatures for macOS.
+
+- Sign an application with a certificate:
+
+`codesign -s {{"My Company Name"}} {{/path/to/App.app}}`
+
+- Verify the certificate of an application:
+
+`codesign -v {{/path/to/App.app}}`