CreateAutomaticDocumentation: make create_full_docu param optional

Also, remove it from the documentation. It (and also the already
undocumented 'entities' argument) are only kept around for
backward compatibility.
Add new magic function GenerateDocumentation
Add makedoc.g demo files for GenerateDocumentation

The included makedoc-PKG.g packages could be used as new
makedoc.g files for indicates packages
PackageInfo.g: Add AutoDoc rec

Specify a custom Copyright and extra includes for CreateMainPage.
Add regenerated title.xml and AutoDoc.xml files

This in particular demonstrates how to use the new function for
packages that do not themselves use AutoDoc.
Enable GAPDoc mode by default.
magic: rewrite bib support
magic: adapt makedoc to recent change
magic: disable scaffolding by default, unless PkgInfo.AutoDoc exists
magic: enable autodoc support if autodoc is a 'suggested' dependency

Previously, this was only done for 'needed' dependencies.
magic: another TODO
magic: rename GenerateDocumentation to AutoDoc
magic: adjust makedoc-*.g files to use AutoDoc()
magic: add docu stub for AutoDoc()
magic: regenerate docs