Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1901504

1. Proposed title of this feature request
Add 'snippet_if_exists' to default kickstart template

2. What is the nature and description of the request?
Improve the usablity of the default kickstart template
For flexability it would be useful to add 'snippet_if_exists' to the post nochroot section of the default kickstart profile.

3. How would the user like to achieve this? (List the functional requirements here)
The section would look like this:
post --nochroot
exec < /dev/tty3 > /dev/tty3
#changing to VT 3 so that we can see whats going on....
+<= snippet_if_exists(template_name + " custom postnochroot") >
/usr/bin/chvt 3
(
cp -va /etc/resolv.conf /mnt/sysimage/etc/resolv.conf
/usr/bin/chvt 1
) 2>&1 | tee /mnt/sysimage/root/install.postnochroot.log
<= section_end -%

4. List any affected packages or components.
Template: kickstart_default.erb