Connect: Add include snippet about starting CrateDB

Author: amotl

docs/connect/_cratedb.md

@@ -0,0 +1,7 @@
+---
+orphan: true
+---
+Start CrateDB using Docker or Podman, then invoke the example program.
+```shell
+docker run --rm --publish=5432:5432 docker.io/crate '-Cdiscovery.type=single-node'
+```