unify build dir for Python and Java (#2171)

* unify build dir for Python and Java

* enable executables auto installed when just running 'make'

* fix plasma_store copy error

* fix cmake error about copying executables

* lint fix

* recover python/setup.py

* enable to copy optional file automatically

* a small fix of path

* lint fix

* lint fix

* lint fix

* Add comment.

python/setup.py

@@ -15,6 +15,9 @@ import setuptools.command.build_ext as _build_ext
 # MANIFEST.in gets applied at the very beginning when setup.py runs
 # before these files have been created, so we have to move the files
 # manually.
+
+# NOTE: The lists below must be kept in sync with ray/CMakeLists.txt.
+
 ray_files = [
     "ray/core/src/common/thirdparty/redis/src/redis-server",
     "ray/core/src/common/redis_module/libray_redis_module.so",