First open source release

Tailscale has made its initial foray into the open-source community by releasing the first bits of its code, specifically the Linux client and its dependent/common code, on GitHub. While acknowledging the presence of numerous rough edges and pending tasks, the team emphasizes their intention to develop the project transparently rather than waiting for perfection. This step marks an early stage in Tailscale's journey towards open-source collaboration, inviting contributions and feedback from the wider community.