Move version to single place; Move 'build' to User Guide; Add 'make publish'

setup.py

@@ -1,10 +1,16 @@
 """vppcfg setuptools setup.py for pip and deb pkg installations"""
 
+import os
 from setuptools import setup
 
+# Read version from _version.py
+version_file = os.path.join(os.path.dirname(__file__), "vppcfg", "_version.py")
+with open(version_file) as f:
+    exec(f.read())
+
 setup(
     name="vppcfg",
-    version="1.0.2",
+    version=__version__,
     install_requires=[
         "requests",
         'importlib-metadata; python_version >= "3.8"',