modules/admin-full: generalize field descriptions in system status page

LuCI is not only used on routers. When running on a NAS or you-name-it
non-router hardware, refering to "Router Name" and "Router Model" in the
system information page was confusing to some users.

git-svn-id: http://svn.luci.subsignal.org/luci/trunk@9669 ab181a69-ba2e-0410-a84d-ff88ab4c47bc