Help: Drop leftover conversion content from manual/*.1.rst

Some text in these manuals is left from the old full help transition
text generated by the automatic conversion process.  Drop it.
Help: Organize manual/*.1.rst sections

Add "Synopsis", "Description", and "See Also" manual page section
headers.  These are typical of .1 man section pages.  Also de-duplicate
the See Also section links using a separate LINKS.txt file included from
each manual.
Help: De-duplicate manual/(cmake|ccmake).1.rst build options

Move common build options out of cmake and ccmake manuals into an
OPTIONS_BUILD.txt file and include it from the original locations.
Make --help-* options available from all command-line tools

Make the standard --help-* options available from all command-line
tools.  Drop options that are no longer supported:

  --copyright, --help-full, --help-html, --help-man,
  --help-compatcommands, --help-custom-modules

De-duplicate Help/manual/*.1.rst help options by using an
OPTIONS_HELP.txt file included from each manual.
Merge topic 'help-manual-cleanup' into next

9b212ad Make --help-* options available from all command-line tools
5dde65a Help: De-duplicate manual/(cmake|ccmake).1.rst build options
ae944d1 Help: Organize manual/*.1.rst sections
4f7d708 Help: Drop leftover conversion content from manual/*.1.rst