net/turnserver: Update 4.10.0 => 4.14.0 (fix 4 CVEs)

Changelogs:
https://github.com/coturn/coturn/blob/4.14.0/ChangeLog
https://github.com/coturn/coturn/releases/tag/4.11.0
https://github.com/coturn/coturn/releases/tag/4.12.0
https://github.com/coturn/coturn/releases/tag/4.13.0
https://github.com/coturn/coturn/releases/tag/4.13.1
https://github.com/coturn/coturn/releases/tag/4.14.0

• Remove dead mirror from MASTER_SITES.
• Switch from http to https in MASTER_SITES.
• Remove unused dependency gettext-runtime.

PR: 296555
Approved by: blanket (fix 4 CVEs)
Security: CVE-2026-53450
Security: CVE-2026-53449
Security: CVE-2026-53448
Security: CVE-2026-43915
Sponsored by: UNIS Labs
Co-authored-by: Vladimir Druzenko <vvd@FreeBSD.org>
MFH: 2026Q2

(cherry picked from commit fd77dbcdcf0659b6d458f06b1da69302cf76655e)