`post-setup-add-components.py` is no more, modify doc

[mzico]

post-setup-add-components.py script is no more in Gluu Server.

We need to update all pages linked to that... i.e.: https://www.gluu.org/docs/casa/4.3/administration/installation/#installation-via-linux-packages

Please update all pages, start with 4.3 for now.