Added node creation by left-click, node drawing and first part of node creator panel drawing

src/graph/node.py

@@ -1,4 +1,5 @@
 class Node:
-    def __init__(self, x: int, y: int):
+    def __init__(self, x: int, z: int, name: str):
         self.x: int = x
-        self.y: int = y
+        self.z: int = z
+        self.name: str = name