Convert to setuptools pacakge.

The normal python package structure and setuptools package are required
for py.typed to be seen by importers, which is needed for callers to
type check use of gdbrunner.

Bug: None
Test: ndk-gdb --help && gdbclient --help
Change-Id: I9a6d65595f9572275e31f08b3678c300a78275d5
2 files changed