Add targetHostIp option, support concurrent STA in Android

[davidalo]

Context
Android 12 introduced WiFi STA/STA concurrency, which allows supported devices to connect to more than one Wi-Fi network at the same time.
For example, when connecting to an IoT device, an Android phone can be connected concurrently to both:

• The primary internet-providing Wi-Fi network

• A local-only IoT Wi-Fi network

From the Android documentation:

The concurrent local-only and internet connection function allows devices to connect to a local-only connection, such as a connection to an IoT device, concurrently with the primary internet-providing network.

Problem
In the current implementation (master branch), the wifiOnly option routes requests through the Wi-Fi interface. However, with STA/STA concurrency there may be multiple Wi-Fi interfaces, and Android can choose either of them. This can cause requests to be routed to the wrong network.

Solution
This PR introduces a new option, targetHostIp, which explicitly specifies the IP address of the device you want to send the request to. This ensures requests are routed to the correct interface when multiple Wi-Fi connections are active.

References
Similar functionality has been implemented in other libraries, e.g.: Rapsssito/react-native-tcp-socket#193