Initial commit: Pezkuwi SubQuery indexer

- pezkuwi.yaml: Relay chain staking indexer (rewards, slashes, pools, transfers, era info)
- pezkuwi-assethub.yaml: Asset Hub indexer (NominationPools, asset transfers)
- GraphQL schema for staking data entities
- Handler mappings from Nova SubQuery base

scripts/python_scripts/telegram_notifications.py

@@ -0,0 +1,38 @@
+import os
+import asyncio
+import telegram
+
+from subquery_api import SubQueryProject, DeploymentInstance
+from singleton import Singleton
+
+
+class TelegramNotifications(metaclass=Singleton):
+    notify_message_title = "⚠️ SubQuery projects error ⚠️"
+    notify_projects_message = []
+
+    def __init__(self) -> None:
+        self.token = os.getenv("TELEGRAM_BOT_TOKEN")
+        self.chat_id = os.getenv("TELEGRAM_CHAT_ID")
+
+    async def send_telegram_message(self, message):
+        bot = telegram.Bot(token=self.token)
+        await bot.send_message(chat_id=self.chat_id, text=message, parse_mode="MarkdownV2")
+
+    def send_notification(self):
+        if len(self.notify_projects_message) != 0:
+            notification_message = self.notify_message_title
+            
+            for project_message in self.notify_projects_message:
+                notification_message += project_message
+            
+            shielded_message = notification_message.replace('-', '\-')
+            asyncio.run(self.send_telegram_message(shielded_message)) 
+        else:
+            pass
+
+    def add_row_in_telegram_notification(self, project: SubQueryProject, instance: DeploymentInstance):
+        notify_project_name = project.name.title()
+
+        self.notify_projects_message.append(
+            f"\n\n*{notify_project_name}* Indexer is unhealthy\!\nProject URL: [Link to project](https://managedservice.subquery.network/orgs/nova-wallet/projects/{instance.project_key.split('/')[1]}/deployments?slot={instance.type})\nExplorer URL: [Link to explorer](https://explorer.subquery.network/subquery/{instance.project_key})\nEnvironment: {instance.type.capitalize()}"
+        )