TXT WiFi: allow different IP address

[akki42]

Hi Benedikt @Bennik2000

First of all: Thank you for this app! It is still working flawlessly, also with current android versions. (E.g on a Samsung Tab S5e with Android 11 / LineageOS 18.1.)

Though I have no idea whether you are still interested in maintaining this app, I would like to propose an - hopefully easy to realize - improvement:
Currently, for a TXT only the default IP address of a TXT in WiFi AP mode (192.168.8.2) is checked.

FtApp/FtApp/FtApp/Fischertechnik/Txt/TxtInterface.cs

Line 30 in 9ce527b

public const string ControllerWifiIp = "192.168.8.2";

FtApp/FtApp/FtApp.Droid/Activities/SelectDevice/InterfaceSearcher.cs

Lines 43 to 45 in 9ce527b

	PossibleIpaddresses = new List<string>
	{
	TxtInterface.ControllerWifiIp,

If the TXT is used in WiFi client mode with a different IP (e.g. via DHCP), it will thus not be found.

It would be great if the user could enter manually a different IP address (or hostname) to be checked. (Maybe even a list of IP adresses or hostnames in case of using multiple TXTs. Alternatively, the android device's current subnet could be scanned, but that would need more substantial changes...)

Would love to see this implemented! Again: Many thanks!