readme: add varlink call to obtain cert
cmd/tlsd-acme: add acme daemon
internal: add NewCertificateFromTLS
cmd/tlsd-fs: add filesystem watcher
contrib/systemd: add example service files
Add internal service helper
readme: add section about protocol
readme: add plans for tlsd-{acme,caddy}
readme: add section about tlsd-fs
cmd/tlsd-fs: new utility
Add basic VarLink protocol
Add README.md with motivation