Zero downtime redeploys

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.

lib/mrsk/commands/traefik.rb

@@ -26,7 +26,7 @@ class Mrsk::Commands::Traefik < Mrsk::Commands::Base
   end
 
   def info
-    docker :ps, "--filter", "name=traefik"
+    docker :ps, "--filter", "name=^traefik$"
   end
 
   def logs(since: nil, lines: nil, grep: nil)