build: migrate env_manager, rbs_gym, rbs_runtime to ament_python

Migrate `env_manager`, `rbs_gym`, and `rbs_runtime` from ament_cmake to ament_python.
Removed unnecessary files including .json and .yaml config files

env_manager/rbs_runtime/setup.py

@@ -0,0 +1,32 @@
+import os
+from glob import glob
+
+from setuptools import find_packages, setup
+
+package_name = "rbs_runtime"
+
+setup(
+    name=package_name,
+    version="0.0.0",
+    packages=find_packages(exclude=["test"]),
+    data_files=[
+        ("share/ament_index/resource_index/packages", ["resource/" + package_name]),
+        ("share/" + package_name, ["package.xml"]),
+        (
+            os.path.join("share", package_name, "launch"),
+            glob(os.path.join("launch", "*launch.[pxy][yma]*")),
+        ),
+    ],
+    install_requires=["setuptools"],
+    zip_safe=True,
+    maintainer="narmak",
+    maintainer_email="ur.narmak@gmail.com",
+    description="TODO: Package description",
+    license="Apache-2.0",
+    tests_require=["pytest"],
+    entry_points={
+        "console_scripts": [
+            "runtime = rbs_runtime.scripts.runtime:main",
+        ],
+    },
+)