DOC: Fill metadata json with meaningfull information

ckeditor5-metadata.json

 {
 	"plugins": [
 		{
-			"name": "My plugin",
-			"className": "MyPlugin",
-			"description": "Adds text to the editor.",
-			"path": "src/myplugin.js",
+			"name": "Complexitywiki Plugins",
+			"className": "ComplexitywikiPlugins",
+			"description": "Adds buttons to insert MathJax delimiters for the complexitywiki.",
+			"path": "src/complexitywiki_plugins.js",
 			"uiComponents": [
 				{
-					"name": "myButton",
+					"name": "displayMathButton",
 					"type": "Button",
-					"iconPath": "theme/icons/ckeditor.svg"
+					"iconPath": "theme/icons/display.svg"
 				}
+                {
+                    "name": "inlineMathButton",
+                    "type": "Button",
+                    "iconPath": "theme/icons/inline.svg"
+                }
 			]
 		}
 	]