Refactor database layer: convert to DatabaseProvider class with initialization

bin/models/log.dart

@@ -0,0 +1,22 @@
+class Log {
+  final int id;
+  final String username;
+  final String action;
+  final DateTime datetime;
+  
+  Log({
+    required this.id,
+    required this.username,
+    required this.action,
+    required this.datetime,
+  });
+  
+  factory Log.fromMap(Map<String, dynamic> map) {
+    return Log(
+      id: map['id'],
+      username: map['username'],
+      action: map['action'],
+      datetime: map['datetime'] as DateTime,
+    );
+  }
+}