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/base.rb

@@ -16,7 +16,7 @@ module Mrsk::Commands
     end
 
     def container_id_for(container_name:)
-      docker :container, :ls, "--all", "--filter", "name=#{container_name}", "--quiet"
+      docker :container, :ls, "--all", "--filter", "name=^#{container_name}$", "--quiet"
     end
 
     private