docs: generate deltachat-rpc-client documentation

To preview the docs, run:
```
scripts/build-python-docs.sh
firefox dist/html/index.html
```

I have removed the Makefile because modern Sphinx Makefile is just a
wrapper for `sphinx-build -M`:
https://github.com/sphinx-doc/sphinx/blob/35965903177c6ed9a6afb62ccd33243a746a3fc0/sphinx/templates/quickstart/Makefile.new_t
and sphinx-quickstart even has an option `--no-makefile`.
`make.bat` makes even less sense.
In `scripts/build-python-docs.sh` I use `sphinx-build` directly
without `make` wrapper.

deltachat-rpc-client/examples/echobot_no_hooks.py

@@ -40,13 +40,13 @@ def main():
 
         while True:
             event = account.wait_for_event()
-            if event["type"] == EventType.INFO:
+            if event["kind"] == EventType.INFO:
                 logging.info("%s", event["msg"])
-            elif event["type"] == EventType.WARNING:
+            elif event["kind"] == EventType.WARNING:
                 logging.warning("%s", event["msg"])
-            elif event["type"] == EventType.ERROR:
+            elif event["kind"] == EventType.ERROR:
                 logging.error("%s", event["msg"])
-            elif event["type"] == EventType.INCOMING_MSG:
+            elif event["kind"] == EventType.INCOMING_MSG:
                 logging.info("Got an incoming message")
                 process_messages()