Fix issue IMGIITRoorkee#1- Error handling for password Manager.

Added a specific `except FileNotFoundError` block to catch missing files.
- Added a generic `except Exception` block to handle any unexpected errors and provide a meaningful error message.
- The program now continues running smoothly and provides helpful feedback when a user attempts to load a non-existent password file.

This improves the robustness of the program, ensuring a smoother user experience by preventing crashes due to missing files.

manager.py

@@ -25,10 +25,15 @@ def create_password_file(self, path, initial_values=None):
 
     def load_password_file(self, path):
         self.password_file = path
-        with open(path, 'r') as f:
-            for line in f:
-                site, encrypted = line.split(":")
-                self.password_dict[site] = Fernet(self.key).decrypt(encrypted.encode()).decode()
+        try:
+            with open(path, 'r') as f:
+                for line in f:
+                    site, encrypted = line.split(":")
+                    self.password_dict[site] = Fernet(self.key).decrypt(encrypted.encode()).decode()
+        except FileNotFoundError:
+            print("Password file at ", path, "was not found. Please do check the file path and try again.")
+        except Exception as e:
+            print("An unexpected error occured: ", e)
 
     def add_password(self, site, password):
         self.password_dict[site] = password