sci-libs/cddlib: new version 094j.

sci-libs/cddlib: new version 094j.

François Bissey had an ebuild for the latest version of this package in
the sage-on-gentoo overlay, so I've imported it with minor changes:

  * Updated to EAPI=7 (no related changes).
  * Dropped the unused autotools.eclass inherit.
  * Changed GPL-2 to GPL-2+, since the files that do have copyright
    headers have the "or any later version" bit.
  * Dropped the DOCS declaration; they're all covered by einstalldocs.
  * Added IUSE=examples.
  * Reworked the documentation/example installation logic. The new
    autotools build system installs everything by default, so if
    the user doesn't want something, we have to kill it from $ED.

I've also added the upstream remote to metadata.xml, and added myself
and François as maintainers in the future.

SageMath uses two cddlib executables only present as of this version,
so it's a prerequisite for moving more of SageMath into the tree.

Closes: https://bugs.gentoo.org/705218
Package-Manager: Portage-2.3.79, Repoman-2.3.16
Signed-off-by: Michael Orlitzky <mjo@gentoo.org>