Documentation: Update the rogomatic(6) man page

[lcn2]

The rogomatic(6) man page (source file is rogomatic.6.in) needs updating.

For example, instead of containing hard coded paths from the original authors, the make rogomatic.6 rule of the Makefile needs to be modified to make use of the ${RGMDIR} and ${ROGUE} make variables.

Replace hard coded paths with symbols of the form @RGMDIR@ and @rogue@, and them modify the sed rule of make rogomatic.6 rule of the Makefile to form the correct man page with up to date paths.

Consider moving the "HISTORY" section in the man page into a new ORIG_HISTORY file and then replace that large text with a pointer to the new file in this repo.

In general, update the man page to make it more useful.