WiFi: store/manage multiple connections

[jotaen4tinypilot]

Follow-up of https://github.com/tiny-pilot/tinypilot/pull/1804. Note: at the time of this writing (2024-06-24) that feature is not yet implemented.

Currently, the WiFi feature is designed so that it allows to store a single WiFi connection. We could enhance the functionality so that users are able to store multiple WiFi networks. That might be useful, if the user carries around their TinyPilot device and uses it in different environments, because the device then could automatically connect to the respective WiFi.

One functionality that we may want to consider is that it’s technically possible to specify the priority of networks: the question is whether we want to offer that, though, because it’s more complex to build.