Rewrite all .r2 scripts in the MASTG-DEMO-xxxx folders to use python and r2pipe

[cpholguera]

Currently in the demos we're using .r2 scripts which are called by the corresponding run.sh in each demo folder. However, they are not flexible enough and cannot run on any generic binary, only work with the one that's on the same folder (as they have hardcoded memory addresses). If we use python scripts with r2pipe we will be able to run the scripts on any binary.