UI: Upgrade stream key link to button in Wizard

Follow up to #2145: https://github.com/obsproject/obs-studio/pull/2145
The wizard has a stream link URL as well, adding the button in the
wizard to match. Additionally, fixing a few  errors in the UI layout
and spacing where items were not padded.

UI/window-basic-auto-config.hpp

@@ -173,7 +173,7 @@ class AutoConfigStreamPage : public QWizardPage {
 	bool ready = false;
 
 	void LoadServices(bool showAll);
-	inline bool IsCustom() const;
+	inline bool IsCustomService() const;
 
 public:
 	AutoConfigStreamPage(QWidget *parent = nullptr);