Support building with MSVC

[BewareMyPower]

Fixes #7

Motivation

The Python client cannot be built with MSVC.

Modifications

CMakeLists.txt:

1. Boost.Python cannot be found on Windows. The component of Boost
   cannot be python3. It should be a specific version like
   python310. Therefore, find all possible components from 3.10 to 3.7
   until the first component is available.
2. For MSVC, link to pulsarWithDeps.lib when LINK_STATIC is ON and
   set the MSVC_RUNTIME_LIBRARY target property to MultiThreaded.
3. Change the suffix from .so to .pyd because Python on Windows
   recognizes *.pyd as the dynamic library.
4. Link to Python library with MSVC, otherwise the symbos cannot be
   found when linking boost-python.

README: tell users how to build Python client on Windows.

Add a workflow to build Python wheels of versions 3.7 to 3.10 on Windows
and verify the build will succeed.

NOTE

With this PR, Windows users still need to put the related
boost_python*.dll under the system path. In future, the boost-python
dependency will be removed. See
#24.

[BewareMyPower]

The Boost.Python dependency is still linked dynamically even if LINK_STATIC is ON. I have struggled for some time and opened an issue here: microsoft/vcpkg#27491. Not sure if it's a bug of Vcpkg or Boost.Python itself.

[BewareMyPower]

@merlimat @Demogorgon314 @RobertIndie Now this Pr is ready to review, PTAL.

I didn't add the packaging workflow. The only dependency is the boost python DLL. I think we only need to upload the .whl and the DLL as the artifacts.

[BewareMyPower]

microsoft/vcpkg#27491 (comment) can link Boost.Python statically, but it requires other libraries are multi-threaded dynamically-linked. Since pulsarWithAllDeps.lib is still multi-threaded statically-linked, there will be a conflict. The solution might be a little complicated, which requires some changes to build the Pulsar C++ client. So this PR still links Boost.Python dynamically.

[merlimat]

@BewareMyPower perhaps the DLL can be included in the wheel file, in similar way as we’re doing in Linux, where “auditwheel” command is fixing the wheel by adding the dependencies.