Hide default footer in docs by hiding default copyright

The default footer only consists of the copyright statement, so we
can get rid of the footer by not showing the copyright.

Instead we show a custom footer thanks to @umcsdon.

docs/source/conf.py

@@ -158,7 +158,7 @@
 #html_show_sphinx = True
 
 # If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-#html_show_copyright = True
+html_show_copyright = False
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the