Remove ch_dochistory, use section_dochistory instead

Like in all other guides, let's place the history in the preface
and use section_dochistory instead of ch_dochistory.

Also, the config guide had a chapter called overview. Mark it as
preface like in all other guides.

Change-Id: I4de28356456286c7f3d7a340cf27f233d52cdfec
Merge "Remove ch_dochistory, use section_dochistory instead"