<Hermetic> Implement CPython2 Launcher in C++.

The launcher is actually a wrapper which will statically link Python
interpreter within the .par file. It is used to bootstrap embedded
interpreter.

The next step is to change/integrate with Soong to make this hermetic .par
generation process more automatic.

Bug: b/62380596

Test: The launcher has been tested using real files:
zip -r hermetic.zip entry_point.txt Stdlib/ runfiles/
cat launcher | cat - hermetic.zip > executable && chmod u+x executable

Change-Id: I293cae2fe74d46766044f3e3c4b654a54d319b67