Improve performance of Db2 mirroring

[durera]

After discussion with the Db2 team ... we can half the size of the content that needs to be mirrored for db2u:

We have both the CPD and "standalone" versions of our operator in the same case bundle, resulting in two sets of images. To keep only the standalone images, you can delete all the image entries matching 11.5.8.0-cn1-8004 and etcd:3.4.14-8004 in their image tags.

So something like this

sed -i '/11.5.8.0-cn1-8004/d' <manifest_file>
sed -i '/etcd:3.4.14-8004/d' <manifest_file>

will safely remove all the CP4D images before you start mirroring