cleanup: revamp the dnssec-dsfromkey man page and help output

cleanup: revamp the dnssec-dsfromkey man page and help output

* Alphabetize the option lists in the man page and help text

* Make the synopses more consistent between the man page and help
  text, in particular the number of different modes

* Group mutually exclusive options in the man page synopses, and order
  options so that it is more clear which are available in every mode

* Expand the DESCRIPTION to provide an overview of the output modes
  and input modes

* Improve cross-references between options

* Leave RFC citations to the SEE ALSO section, and clarify which RFC
  specifies what

* Clarify list of digest algorithms in dnssec-dsfromkey and dnssec-cds
  man pages

(cherry picked from commit 6ca8e130ace087ce476d601c71f67a96220438e3)