feat: Add runtime flag to container create and run commands (apple#1049) (apple#1109)

## Type of Change
- [ ] Bug fix
- [ ] New feature  
- [ ] Breaking change
- [ ] Documentation update

## Motivation and Context
Fixes apple#1049 
-  Add --runtime option for Flags.Management
-  Apply runtime handler in containerConfigFromFlags
-  Update command-reference.md doc

## Testing
- [x] Tested locally
- [ ] Added/updated tests
- [ ] Added/updated docs

Co-authored-by: J Logan <john_logan@apple.com>

Author: iko1

Sources/Services/ContainerAPIService/Client/Flags.swift

@@ -221,6 +221,9 @@ public struct Flags {
 
         @Flag(name: .long, help: "Mount the container's root filesystem as read-only")
         public var readOnly = false
+
+        @Option(name: .long, help: "Set the runtime handler for the container (default: container-runtime-linux)")
+        public var runtime: String?
     }
 
     public struct Progress: ParsableArguments {

Sources/Services/ContainerAPIService/Client/Utility.swift

@@ -248,6 +248,10 @@ public struct Utility {
         config.ssh = management.ssh
         config.readOnly = management.readOnly
 
+        if let runtime = management.runtime {
+            config.runtimeHandler = runtime
+        }
+
         return (config, kernel)
     }
 

docs/command-reference.md

@@ -65,6 +65,7 @@ container run [<options>] <image> [<arguments> ...]
 *   `--tmpfs <tmpfs>`: Add a tmpfs mount to the container at the given path
 *   `-v, --volume <volume>`: Bind mount a volume into the container
 *   `--virtualization`: Expose virtualization capabilities to the container (requires host and guest support)
+*   `--runtime`: Set the runtime handler for the container (default: container-runtime-linux)
 
 **Registry Options**
 
@@ -214,6 +215,7 @@ container create [<options>] <image> [<arguments> ...]
 *   `--tmpfs <tmpfs>`: Add a tmpfs mount to the container at the given path
 *   `-v, --volume <volume>`: Bind mount a volume into the container
 *   `--virtualization`: Expose virtualization capabilities to the container (requires host and guest support)
+*   `--runtime`: Set the runtime handler for the container (default: container-runtime-linux)  
 
 **Registry Options**