chore: Add scripts to automate plugin extensions setup

[tustanivsky]

This PR automates setup for platform extensions allowing developers to work on console-specific code directly in the main plugin repository without manual file copying (see Building the Unreal Engine extension step in corresponding README.md files).

New PowerShell scripts pre-build the binaries required for consoles and copy them to sample project dir accordingly. They also symlink extension source files so that changes made in sentry-unreal are automatically tracked in the extension repositories.

Usage example:

# One-time: Set environment variables
$env:SENTRY_SWITCH_PATH = "D:\projects\sentry-switch"
$env:SENTRY_PLAYSTATION_PATH = "D:\projects\sentry-playstation"
$env:SENTRY_XBOX_PATH = "D:\projects\sentry-xbox"

# Setup all platforms
./scripts/init-consoles.ps1 -All

# Setup specific platforms
./scripts/init-consoles.ps1 -Switch -PS5

# Setup individual platform without configuring environment variables
./scripts/init-console-ext.ps1 -Platform Switch -ExtensionPath D:\projects\sentry-switch

Workflow:

1. Validate extension repository paths/structure
2. Build platform extension using CMake (fresh build with platform-specific presets)
3. Create sample/Platforms/{Platform}/Plugins/Sentry/ directory structure
4. Copy pre-built native libraries and headers from build output
5. Symlink extension's source files (.uplugin, .Build.cs, Private/) for live editing

Closes #1009

#skip-changelog