initial readme with setup.sh usage and dropbear unlock

README.md

@@ -0,0 +1,12 @@
+usage:
+```sh
+./setup.sh <server> <fqdn>
+
+# example:
+./setup.sh ovh token.lubi.link
+```
+
+after connecting to dropbear:
+```sh
+/bin/cryptroot-unlock && exit
+```