Add support for specifying custom debugger rules in config file

[fatshark-awr]

This is a supplement or alternative to #196. Would avoid the need to update the extension if extra debugger rules are needed by someone in the future.

Copied from the readme additions:

Custom Debugger Rules

The extension ships with built-in support for common C/C++ debugger flavors (Windows Local/Remote, Linux, WSL, Android, Oasis NX, etc.). If your project uses a debugger flavor that is not listed above, you can register it via a JSON config file without modifying the extension.

Create a file at:

%LOCALAPPDATA%\SmartCmdArgs\custom_debugger_rules.json

The file contains a JSON array of rule objects. Each rule maps a debugger flavor (the DebuggerFlavor value in your .vcxproj.user) to the project properties the extension should read from and write to:

[
  {
    "RuleName": "MyCustomDebugger",
    "ArgsPropName": "RemoteDebuggerCommandArguments",
    "EnvPropName": "RemoteDebuggerEnvironment",
    "WorkDirPropName": "RemoteDebuggerWorkingDirectory",
    "LaunchAppPropName": "RemoteDebuggerCommand"
  }
]

Field	Required	Description
RuleName	Yes	The debugger flavor name, matching the DebuggerFlavor property in the .vcxproj.user file.
ArgsPropName	Yes	The property name for command line arguments.
EnvPropName	No	The property name for environment variables.
WorkDirPropName	No	The property name for the working directory.
LaunchAppPropName	No	The property name for the launch application/command.

Rules with a RuleName that duplicates a built-in rule are ignored. Errors loading the file are logged to the Visual Studio Activity Log.

To find the correct RuleName for your debugger, set the debugger flavor and some arguments in Visual Studio, save, and inspect the <DebuggerFlavor> value under DebuggerGeneralProperties in your .vcxproj.user file.