Fixed Picasso + refactors

- Removed comment

- Moved SSLSettings to its own top-level class

- Fixed picasso not setting SSL settings and failing to load images over
  self-signed connection

app/src/main/java/com/github/gotify/SSLSettings.java

@@ -0,0 +1,11 @@
+package com.github.gotify;
+
+public class SSLSettings {
+    public boolean validateSSL;
+    public String cert;
+
+    public SSLSettings(boolean validateSSL, String cert) {
+        this.validateSSL = validateSSL;
+        this.cert = cert;
+    }
+}