First cut of log on page (#9)

- Add session support
- Refactor security handling to use db connection
- Fix db path issue

src/lib/Key.php

@@ -2,10 +2,10 @@
 
 class Key {
 
-    /** @var string The $_REQUEST key for teh current user's e-mail address */
+    /** @var string The $_SESSION key for the current user's e-mail address */
     public const string USER_EMAIL = 'FRC_USER_EMAIL';
 
-    /** @var string The $_REQUEST key for the current user's ID */
+    /** @var string The $_SESSION key for the current user's ID */
     public const string USER_ID = 'FRC_USER_ID';
 
     /** @var string The $_REQUEST key for the array of user messages to display */