Rename markdown files to match current chapter and section names

[ahouseholder]

Fixes #254

• For short chapters, use CC_name.md
• When chapters are too big for one file an need to be split up, use CC_SS_name.md

Where

• CC = zero-padded chapter number
• SS = zero-padded section number (chapter intro SS should be 00)
• name = a string derived from the first heading in the file

Also modify the Makefile

• generate non-versioned filenames
• use current commit hash as fix version
  • yes, this violates strict incremntal SemVer, but I think this is ok because the makefile is only producing a review draft anyway

Finally

• Fix the second Acknowledgements section which was really a copyright notice
• Bump the copyright year to 2023