doc: add ivhshmem hv-land introduction

Ivshmem hv-land solution emulates the ivshmem device in hypervisor
and the shared memory is reserved in the hypervisor's memory space.
And it can provide inter-vm communication for both pre-launched and
post-launched VMs.

This patch introduces the ivshmem hv-land solution including what
ivshmem hv-land is and how to use it.

Signed-off-by: Yuan Liu <yuan1.liu@intel.com>

doc/develop.rst

@@ -73,6 +73,7 @@ Enable ACRN Features
    tutorials/acrn_on_qemu
    tutorials/using_grub
    tutorials/pre-launched-rt
+   tutorials/enable_ivshmem
 
 Debug
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