graphics/sxiv: Update to v26

• Set LICENSE_FILE.
• Update LIB_DEPENDS.
• Install icons and a desktop file.
• Remove the local patches and use MAKE_ARGS instead.
• Reset MAINTAINER (3 timeouts)
• Adopt port

PR: 244040
Reviewed by: mat
Approved by: solene@bsd.zplay.eu (maintainer timeout)
Differential Revision: https://reviews.freebsd.org/D23616