docs: add comprehensive roadmap for the GOE framework

- Introduced `ROADMAP.md` outlining the current state, gap analysis, and phased development plan for the GOE framework.
- Detailed module-specific requirements for authentication, jobs, migrations, CLI, testing, and security.
- Articulated design principles, future enhancements, and community contribution guidelines.
- Included references to core technologies like Uber Fx, GoFiber, GORM, and Redis Streams.

Author: anxuanzi