[PROBLEM] Custom Netmask Option

[hrast01]

I have a lot of random devices on my my home network, so I moved from using a /24 to a /23 netmask when I re-architected it..  This became an issue because I can only choose a netmask from a predefined list, and 255.255.254.0 is not an option. I did find where the netmask gets written to and updated it there, so I know how to fix this, but it would be nice if I didn't have immediately go into the cli after bringing it up.  I don't have to ssh in to configure anything else, so this seems like an outlier in how one would want the project to function.

[Tim Curtis]

I'll add to the TODO list for upcoming 9.0.0 release to switch to manually entered net mask in the static IP section.