Change to FreeBSD release scheduling and support period

FreeBSD is implementing changes to its release scheduling and support period. Starting with FreeBSD 15.x, the support duration for stable branches will be reduced from 5 to 4 years after the initial release. A more predictable release schedule is being established, with minor releases from supported stable branches expected quarterly. These adjustments aim to streamline the release process, encourage more frequent releases to ease pressure on feature inclusion, and provide better estimates for long-term planning. The FreeBSD core team has approved these changes, with a detailed schedule of upcoming releases provided. The new quarterly schedule will require feature submissions by specific deadlines and beta testing in designated months. The goal is to offer users a more predictable upgrade cycle while balancing new feature availability and maintaining supported releases effectively. These modifications are part of efforts led by Colin Percival, the FreeBSD Release Engineering Lead, to enhance the project's development and support processes.