Add AP_STA (esp-wifi-mesh) mode?

[rdragonrydr]

I'd really like if there was an option in the config to make the AP stay active even if the WiFi is connected as a client.

Unfortunately, due to the way the connection code is implemented here, I'm rather overwhelmed and can't really implement it myself.

Desired feature:

An entry in the config file like so:
//Uncomment the following line to force the access point to stay up
// #define AP_STA

When this feature is active, the ESP32 will broadcast an access point of the specified (via the usual method in the config) SSID even while it may or may not connect to another network as a client.

I think it can be done by changing the second clause of the condition on the AP section of the code to be access_point && ([not connected to wifi] || AP_STA_CONFIG) but I am having trouble figuring out if that would have side effects.

[easytarget]

AKA: https://www.espressif.com/en/products/sdks/esp-wifi-mesh/overview
A good idea. But this is something to be done as part of a general wifi overhaul. And I don't want to be testing and debugging this myself to be honest.
See also #212