Handle soldat:// URI

[helloer]

As a user I want to easily run the game via soldat:// uri. Format of soldat uri is: soldat://server_ip:server_port/server_password server_port and server_password are optional.

Example:

soldat://8.8.8.8
soldat://127.0.0.1:23073/serverpass

• Register soldat:// protocol (https://www.electronjs.org/docs/api/app#appsetasdefaultprotocolclientprotocol-path-args) and parse provided data, handler should fill up ipbox (ServerIP/Port/Password fields) automatically and start the game
• Same thing should happen when you paste(Ctrl+V) soldat:// link in the lobby tab

[rzaba0]

I've added support for soldat:// links. Registering of soldat:// protocol works on Windows. It could also be added on Linux and macOS, but it requires different approaches.

Features:

• [x] Pasting soldat:// link in Server IP field in Lobby tab fills up all fields, but does not start the game.
• [x] Launcher can receive a soldat:// link as a command-line argument (./soldat-launcher soldat://127.0.0.1:23074). If you run the launcher like this, it fills up the fields in Lobby tab and starts the game right away.
• [X] We allow only one process of the launcher to run at a time. If you run the launcher while there is an instance running already, we just restore the window and handle command-line arguments (if any) from there. The reason is that we don't want to spawn a new launcher every time you click a soldat:// link.
• [x] Registering of soldat:// protocol on Windows. Clicking on a soldat:// link will run the launcher with the link as a command-line argument.
• [ ] Registering of soldat:// protocol on Linux
• [ ] Registering of soldat:// protocol on macOS