Rename global list <proxies> to <all_proxies>. This better highlights
the difference with the other list <main_proxies>. The first one contain
every proxy instances, whereas the second list is only a subset of user
visible proxies.
In the future, it should be sufficient to only keep <all_proxies> list.
However, this requires careful code analysis, in particular to ensure
proxies iteration are always executed with the proper capabilities
filter.