feat: add VastAI instance management functions

- Added functions to manage VastAI instances:
- `attach_sshkey_to_instance`
- `stop_instance`
- `destroy_instance`
- `launch_instance`
- `start_instances`
- `start_instance`
- Updated example to demonstrate new functions.

Co-authored-by: mariobassem12 <mariobassem12@gmail.com>

examples/develop/vastai/vastai_example.vsh

@@ -22,3 +22,45 @@ create_instance_res := va.create_instance(
 	}
 )!
 println('create instance res: ${create_instance_res}')
+
+attach_sshkey_to_instance_res := va.attach_sshkey_to_instance(
+	id:     1
+	ssh_key: "ssh-rsa AAAA..."
+)!
+println('attach sshkey to instance res: ${attach_sshkey_to_instance_res}')
+
+stop_instance_res := va.stop_instance(
+	id:     1
+	state: "stopped"
+)!
+println('stop instance res: ${stop_instance_res}')
+
+destroy_instance_res := va.destroy_instance(
+	id:     1
+)!
+println('destroy instance res: ${destroy_instance_res}')
+
+// For some reason this method returns an error from their server, 500 ERROR
+// (request failed with code 500: {"error":"server_error","msg":"Something went wrong on the server"})
+launch_instance_res := va.launch_instance(
+	// Required
+	num_gpus: 1,
+	gpu_name: "RTX_3090",
+	image:    'vastai/tensorflow',
+	disk:     10,
+	region: "us-west",
+
+	// Optional
+	env: "user=7amada, home=/home/7amada",
+)!
+println('destroy instance res: ${launch_instance_res}')
+
+start_instances_res := va.start_instances(
+	ids:     [1, 2, 3]
+)!
+println('start instances res: ${start_instances_res}')
+
+start_instance_res := va.start_instance(
+	id:     1
+)!
+println('start instance res: ${start_instance_res}')