games/openomf: Update 0.6.5 => 0.8.3, improve port

Changelogs:
https://github.com/omf2097/openomf/releases/tag/0.7.0
https://github.com/omf2097/openomf/releases/tag/0.7.1
https://github.com/omf2097/openomf/releases/tag/0.8.0
https://github.com/omf2097/openomf/releases/tag/0.8.1-rc2
https://github.com/omf2097/openomf/releases/tag/0.8.1-rc3
https://github.com/omf2097/openomf/releases/tag/0.8.1
https://github.com/omf2097/openomf/releases/tag/0.8.2
https://github.com/omf2097/openomf/releases/tag/0.8.3-fk1
https://github.com/omf2097/openomf/releases/tag/0.8.3



Improve port:
- Add github to WWW.
- Add LICENSE.
- Switch to default cmake build instead of cmake:insource.
- Parapetrize "openomf" with "${PORTNAME}" in several places.
- Fix warnings from portclippy and portlint.

PR:		289093
Co-authored-by: Vladimir Druzenko <vvd@FreeBSD.org>