Remove note about cloning and editing templates

Users should never clone and edit templates. Instead, if they really
need to run custom code before or after registration or provisioning
workflows, they should use "custom pre" and "custom post" snippets as
documented. This way they do not lose support by the community/vendor.

Also, there's configuration management.

Fixes #4256

Author: maximiliankolb

guides/common/modules/proc_booting-virtual-machines.adoc

@@ -25,13 +25,6 @@ endif::[]
 * You have configured your iPXE environment.
 For more information, see xref:Configuring_iPXE_Environment_{context}[].
 
-[NOTE]
-====
-You can use the original templates shipped in {Project} as described below.
-If you require modification to an original template, clone the template, edit the clone, and associate the clone instead of the original template.
-For more information, see xref:common/modules/proc_running-custom-code-during-host-provisioning.adoc#running-custom-code-during-host-provisioning[].
-====
-
 .Procedure
 . In the {ProjectWebUI}, navigate to *Hosts* > *Templates* > *Provisioning Templates*.
 ifdef::satellite[]
@@ -67,3 +60,6 @@ endif::[]
 . Select the *Templates* tab.
 . In *Provisioning Templates*, click *Resolve* and verify that the *iPXE template* resolves to the required template.
 . Click *Submit* to save host settings.
+
+.Additional resources
+* xref:running-custom-code-during-host-provisioning[]

guides/common/modules/proc_chainbooting-ipxe-from-pxelinux.adoc

@@ -25,13 +25,6 @@ Chainbooting iPXE has the following workflow:
 * You have configured your iPXE environment.
 For more information, see xref:Configuring_iPXE_Environment_{context}[].
 
-[NOTE]
-====
-You can use the original templates shipped in {Project} as described below.
-If you require modification to an original template, clone the template, edit the clone, and associate the clone instead of the original template.
-For more information, see xref:common/modules/proc_running-custom-code-during-host-provisioning.adoc#running-custom-code-during-host-provisioning[].
-====
-
 .Procedure
 . In the {ProjectWebUI}, navigate to *Hosts* > *Templates* > *Provisioning Templates*.
 . Search for the required PXELinux template:
@@ -75,3 +68,6 @@ endif::[]
 . Set the *PXE Loader*:
 * Select `PXELinux BIOS` to chainboot iPXE (`ipxe.lkrn`) from PXELinux.
 * Select `iPXE Chain BIOS` to load `undionly-ipxe.0` directly.
+
+.Additional resources
+* xref:running-custom-code-during-host-provisioning[]