Adds a Connected devices column to the Port Configuration table, fed by
the shared walkL2() helper. A port with a single MAC behind it shows the
MAC directly; several are shown as a count with the full list in the
cell tooltip, since picking one of many to display would suggest it was
"the" device. The walk restarts 15 seconds after each completion and
starts 3 seconds after page load to stay clear of the initial status and
MTU requests. A walk that ends without ok keeps the previous cells,
since an incomplete table would blank ports that have devices behind
them. Translations for the three languages included.
This reduces the number of .js which are pulled by the browser
when loading a http page, which should reduce the loading time.
Also prepare for device-dependent logical to physical port
mappings.