Add TODO section to README

Added a TODO list to outline pending tasks for the app, including creating an icon, splash screen, and enabling app signing for Play Store distribution. This provides clear guidance for future development steps.

Author: YeisonCardona

README.md

@@ -64,3 +64,9 @@ BUILDTOOL=35.0.0
 P4A_VERSION=2024.1.21
 CYTHON_VERSION=3.0.4
 ```
+
+## TODO List
+
+- [ ] Add icon for the app
+- [ ] Add splash screen for the app
+- [ ] Add the possibility to sign the app (ready for the Play store)