[Feature Request] Expose MTU to host manager webGUI on both Linux appliance types

[mikeely]

Justification: setting MTU to 9000 is very common for storage interfaces but the default value of 1500 is highly preferred for management interfaces. Currently the only way to set MTU is via root shell, which is both (deliberately) difficult to do and also creates the opportunity for other system changes to be made outside the simple scope of editing MTU whether deliberately or by accident.