Accounts for the 2.9.10 security release and allows testing Traefik 3 betas.
* Use `image` to configure a specific Traefik Docker image.
* Default to `traefik:v2.9` to track future 2.9.x minor releases rather
than tightly pinning to `v2.9.9`.
* Support images from the configured registry.
References #165
When deploying check if there is already a container with the existing
name. If there is rename it to "<version>_<random_hex_string>" to remove
the name clash with the new container we want to boot.
We can then do the normal zero downtime run/wait/stop.
While implementing this I discovered the --filter name=foo does a
substring match for foo, so I've updated those filters to do an exact
match instead.