Move Plugin Client and Slots docs to API section

docs/source/api/client.md

@@ -1,7 +1,10 @@
 ---
-title: Plugins API
-permalink: /plugins-api/
+title: Client Plugin API
+permalink: /api/client/
+toc: true
+class: configuration
 ---
+
 We created a set of utilities to make it easier to create and add functionality to plugins.
 Feel free to check all the utilities here:  `talk/plugin-api`.
 

docs/source/api/server.md

@@ -524,4 +524,4 @@ module.exports = {
   }
 };
 
-```
+```

docs/source/api/slots.md

@@ -1,6 +1,8 @@
 ---
-title: Slots and Plugins
-permalink: /slots-and-plugins/
+title: Plugin Slots API
+permalink: /api/slots/
+toc: true
+class: configuration
 ---
 
 Plugins make use of **"slots"** in order to change Talk's interface.