Make it clear that Network Connections persistence feature stores geo-location information

E.g. apparently 802-11-wireless.seen-bssids is persisted. This can be a problem e.g. when connecting to Wi-Fi access points whose ESSID is widespread (e.g. ISPs Wi-Fi sharing programs for DSL subscribers). This can perhaps be addressed at the same time as #10803.

However, the problem is more general, and exist to some degree even if we did not store BSSID:s: a list of Wi-Fi networks is already geo-location information. So I guess this should be made clear in the persistence configuration interface + doc.

This was originally reported on #10803-note_6.

For the record this is still the case on sid with NM 1.12.2-2.

Related issues

• Related to #10803

Original created by @intrigeri on 10985 (Redmine)