bond: T6709: add EAPoL support (backport #4069) (#4076)

• ethernet: T6709: move EAPoL support to common framework

Instead of having EAPoL (Extensible Authentication Protocol over Local Area
Network) support only available for ethernet interfaces, move this to common
ground at vyos.ifconfig.interface making it available for all sorts of
interfaces by simply including the XML portion

  #include <include/interface/eapol.xml.i>

(cherry picked from commit 0ee8d5e35044e7480dac6a23e92d43744b8c5d36)

• bond: T6709: add EAPoL support

(cherry picked from commit 8eeb1bdcdfc104ffa77531f270a38cda2aee7f82)

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Co-authored-by: Christian Breunig <christian@breunig.cc>