Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - Merge "[baremetal] PDF-based network config" into stable/euphrates
  - [baremetal] PDF-based network config

    This change extends current PDF/IDF support with:
    - dynamic interface / vlan definition;
    - dynamic interface and/or bridge allocation of installer networks on
      top of interfaces (physical or vlans);

    This allows us to drop hardcoded interface names and vlan / bridge
    configuration in favor of a runtime determined model based on PDF/IDF.

    For now, we duplicate common jinja variable definitions in each
    template, but this will later be moved to a common include file.

    JIRA: FUEL-275

    Change-Id: Ia80a66dbdf898b0bd0a4fb99d069ce9ebe33fa65
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit c360b972649028d2613fc8561899c2c8b7f71832)

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 8cd105a..80fa21c 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 8cd105aefb88b4a57dd27019ff37bf19cee9c4d9
+Subproject commit 80fa21c1cf4eea0f41438bc0f7509af7ee237dc1