Fix wheel build

[vlad-nn]

• Added build dependencies into pyproject.toml
• Added runtime dependencies to install_requires
• Moved lap version info into lap/version.py so it will be available in setup.py without importing lap
• Removed import lap form setup.py
• Removed __LAP_SETUP__ logic because it is not needed anymore

Now you can build lap wheel normal way (not only in editable mode) and deploy it to PyPI.

[vlad-nn]

@gatagat , looks like this PR resolves both build and install dependencies on numpy. It also elimiminates the need to import lap from setup.py, which produced wheel build error.

[vlad-nn]

For some reason APPVEYOR build fails on Python 3.8 configuration with scipy compilation errors.