Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - Merge "[baremetal] idf support for different board types" into stable/euphrates
  - [baremetal] idf support for different board types

    This modification enables having different models of target nodes
    but restricts them to two groups of the same kind assuming:
     - 3 KVMs will be same model and have the same NIC names
     - 2 Compute nodes will be the same model and have same NIC names

    This is an ad-hoc change for arm-pod7. Will work for all other setups
    but the jinja2 logic should be evetually extended to support a per
    board approach, allowing any board to be any kind

    Change-Id: Ie994d661e3dbe5b9a33d290a850a6152cf320c86
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit ee149500e0e6bde0152aa56140046a2d1b995eb4)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 66d147d..78878a3 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 66d147d4d0f471e5a75d9d1691ea42dad36f01ac
+Subproject commit 78878a33010e0bbec01196dfc5cc376567512376