Massive refactor of code into classes, improve security on the image/file upload handler. Clean up the init.php into a config.php and refactor everything else to work around it.

Resolves issues #13 #14 and #16

cms/src/NeoCMS/Authentication.php

@@ -0,0 +1,59 @@
+<?php
+
+namespace NeoCMS;
+
+class Authentication
+{
+    private $credentials;
+
+    public function __construct(array $credentials)
+    {
+        session_start();
+        $this->credentials = $credentials;
+    }
+
+    /**
+     * Logs a user into the CMS
+     * @param $username
+     * @param $password
+     * @return bool
+     */
+    public function login($username, $password)
+    {
+        if (!empty($this->credentials[$username]) && $this->credentials[$username] === $password) {
+            $_SESSION['loggedIn'] = true;
+            $_SESSION['loggedInUser'] = $username;
+            return true;
+        }
+
+        $_SESSION['loggedIn'] = false;
+        return false;
+    }
+
+    /**
+     * Checks if a user has logged in
+     * @return bool
+     */
+    public function isLoggedIn(): bool
+    {
+        return $_SESSION['loggedIn'] ?? false;
+    }
+
+    /**
+     * Returns the user logged in
+     * @return string
+     */
+    public function getLoggedInUser(): string
+    {
+        return $_SESSION['loggedInUser'] ?? 'Not logged in';
+    }
+
+    /**
+     * Destroy the session
+     * @return void
+     */
+    public function logout()
+    {
+        session_destroy();
+    }
+}