Add Proxy mode

[hosseinTSR]

سلام و خسته نباشید به توسعه دهندگان عزیز برنامه امکان اضافه شدن حالت پراکسی مود به برنامه برای زنده کردن کانفیگ های سایر برنامه ها طی آپدیت های بعدی وجود داره؟

[debMan]

It would be nice to have an option alongside other options in application settings that selects the app functionality mode:

• VPN mode: which utilizes the native Android tun interface
• Proxy mode: which listens on loopback on a specific port, to use with other proxy apps like V2rayNG or shadowsocks

With this option, domain-based routing is achieved with the mediation of other applications. Also, with this option, opening the termux is no longer required.

Seems its complementary to #161