python: Populate README with minimal context.

This is very basic, but it should give enough pointers to get started.

Signed-off-by: Stephen Finucane <stephen@that.guru>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

python/README.rst

@@ -1 +1,74 @@
-Python library for working with Open vSwitch
+..
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+      Convention for heading levels in Open vSwitch documentation:
+
+      =======  Heading 0 (reserved for the title in a document)
+      -------  Heading 1
+      ~~~~~~~  Heading 2
+      +++++++  Heading 3
+      '''''''  Heading 4
+
+      Avoid deeper levels because they do not render well.
+
+============
+Open vSwitch
+============
+
+The ``openvswitch`` package provides the `official Python language bindings`__
+for `Open vSwitch`__. They are developed in-tree as part of the `Open vSwitch
+Package`__.
+
+.. __: https://docs.openvswitch.org/en/latest/topics/language-bindings/
+.. __: https://docs.openvswitch.org/en/latest/
+.. __: https://github.com/openvswitch/ovs/tree/main/python/ovs
+
+
+Installation
+------------
+
+You can install the package using ``pip``:
+
+.. code-block:: shell
+
+    $ pip install ovs
+
+The package include an optional flow parsing library. To use this package, you
+must install its required dependencies. The ``flow`` `extra`__ is provided for
+this purpose:
+
+.. code-block:: shell
+
+    $ pip install ovs[flow]
+
+.. __: https://packaging.python.org/en/latest/tutorials/installing-packages/#installing-extras
+
+
+Documentation
+-------------
+
+Documentation is included in the Python source. To view this, you can install
+the package and use `pydoc`__. For example:
+
+.. code-block:: shell
+
+    $ python -m pydoc ovs
+
+Alternatively, you can use the ``help`` function from the Python REPL:
+
+.. code-block:: python
+
+    >>> import ovs
+    >>> help(ovs)
+
+.. __: https://docs.python.org/3/library/pydoc.html