Make wxPython optional for Python packaging purposes

wxPython is unnecessary for the automated test suite. Additionally, the GTK interface still works under PyGObject in GTK 3, so re-expose that.

MANIFEST.in

@@ -3,6 +3,7 @@ include chirp/share/*.png
 include chirp/share/*.ico
 include chirp/share/*.1
 include chirp/stock_configs/*
+include chirpw
 include COPYING
 include *requirements.txt
 graft tests

setup.py

@@ -12,13 +12,17 @@ setup(name='chirp',
       url='https://chirp.danplanet.com',
       python_requires=">=3.7,<4",
       install_requires=[
-          'wxPython',
           'pyserial',
           'six',
           'future',
           'importlib-resources;python_version<"3.10"'
       ],
+      extras_require={
+          'wx': ['wxPython'],
+          'gtk': ['PyGObject']
+      },
       entry_points={
           'console_scripts': ["chirp=chirp.wxui:chirpmain"],
       },
+      scripts=['chirpw'],
       )