devel/oniguruma: Update to 6.7.0

Additional changes:

• Took ownership. Maintainer's timeout expired, and my repeated requests to the maintainer went unanswered.
• Rewrote the package description. Also submitted it to the upstream with the suggestion to replace the current description.
• Used tarballs accoding to the policy.
• Added the STATISTICS port option to reflect the option in configure.

PR: 224810
Submitted by: myself
Approved by: tcberner (mentor), mat
Differential Revision: https://reviews.freebsd.org/D13903