docs: Start documenting VM templating

Let's add some details about VM templating, focusing on the VM memory
configuration only.

There is much more to VM templating (VM state? block devices?), but I leave
that as future work.

Message-ID: <20230906120503.359863-10-david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 00562f9..3cf5355 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2963,6 +2963,7 @@
 S: Maintained
 F: backends/hostmem*.c
 F: include/sysemu/hostmem.h
+F: docs/system/vm-templating.rst
 T: git https://gitlab.com/ehabkost/qemu.git machine-next
 
 Cryptodev Backends