[Dockerfile] adding execution of script/post-update, cleanup phase

script/post-update.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+# Remove scripts
+rm -rf /equo-rescue-generate.exp
+rm -rf /equo.sql
+rm -rf /generate-equo-db.sh
+rm -rf /post-upgrade.sh
+rm -rf /sabayon-configuration-build.sh
+rm -rf /sabayon-configuration.sh
+rm -rf /post-upgrade.sh
+
+# Cleaning portage metadata cache
+rm -rf /usr/portage/metadata/md5-cache/*
+rm -rf /var/log/emerge/*
+rm -rf /var/log/entropy/*
+rm -rf /root/* /root/.*
+rm -rf /etc/zsh
+
+rm -rf /post-update.sh
+
+# Writing package list file
+equo q list installed -qv > /etc/sabayon-pkglist