ncm-network: nmstate - add additional route rule parameters

[aka7]

provide additional route rule parameters for nmstate config as defined in https://nmstate.io/devel/yaml_api.html#routes

• Why the change is necessary. allow creation of route rules with all options.
• What backwards incompatibility it may introduce. none.

[aka7]

@jrha created this for discussion on if there will a way to create sperate schemas for nmstate only options. something to think about. as discussed before.

this isnt urgent but at some point we may need to create unreachable routes and only way to do this with nmstate is through route-rules.

[jrha]

I'll try and do some testing to establish a way of making the schema modular, but otherwise having these options as a separate nmstate sub-dict would seem cleanest.