Network settings must not list per-interface gateways

[AlexanderAmelkin]

As discussed in the following issues in other parts of openbmc project, on non-router systems there is no such concept as per-interface gateway:

openbmc/openbmc#2671
openbmc/phosphor-networkd#22

Hence, there is no need to have the associated fields in web-ui. They only confuse the users:

[AlexanderAmelkin]

Additionally, the ids of inputs for "Gateway" and for "Netmask prefix length" are confused in HTML.
The "Gateway" input has id="net-config__subnet" whereas the "Netmask prefix..." input has id="net-config__default-gateway".

[susantjasinski]

related issue #62

[jandraa]

@AlexanderAmelkin The design team has updated the UI proposal, please review at https://ibm.invisionapp.com/share/RQNYHJ0VBDY#/319002386_V2_Networking_Mutliple_VLAN . The corresponding issue is the one tagged above by Susan

[AlexanderAmelkin]

@jandraa, thank you for the update!

[derick-montague]

This will be addressed with story #62.