Merge branch 'main' into pr/205

* main:
  Simplify domain language to just "boot" and unscoped config keys
  Retain a fixed number of containers when pruning
  Don't assume rolling back in message
  Check all hosts before rolling back
  Ensure Traefik service name is consistent
  Extend traefik delay by 1 second
  Include traefik access logs
  Check if we are still getting a 404
  Also dump load balancer logs
  Dump traefik logs when app not booted
  Fix missing for apt-get
  Report on container health after failure
  Fix the integration test healthcheck
  Allow percentage-based rolling deployments
  Move `group_limit` & `group_wait` under `boot`
  Limit rolling deployment to boot operation
  Allow performing boot & start operations in groups

lib/mrsk/commander.rb

@@ -51,6 +51,14 @@ class Mrsk::Commander
     end
   end
 
+  def boot_strategy
+    if config.boot.limit.present?
+      { in: :groups, limit: config.boot.limit, wait: config.boot.wait }
+    else
+      {}
+    end
+  end
+
   def roles_on(host)
     roles.select { |role| role.hosts.include?(host.to_s) }.map(&:name)
   end