setup: add homeserver as console script

With this change, it will be added to `$out/bin` in `nixpkgs` directly.
This became necessary since our old workaround, calling it as script,
doesn't work anymore since the shebangs were removed[1].

[1] matrix-org#10415

Signed-off-by: Maximilian Bosch <maximilian@mbosch.me>

setup.py

@@ -152,6 +152,11 @@ def exec_file(path_segments):
     long_description=long_description,
     long_description_content_type="text/x-rst",
     python_requires="~=3.6",
+    entry_points={
+        'console_scripts': [
+            'homeserver = synapse.app.homeserver:main'
+        ]
+    },
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Topic :: Communications :: Chat",