feat(migrations): add initial migration setup and performance indexes

- Introduced .pgmrc.json and migrate.json for node-pg-migrate configuration.
- Added multiple migration files to create performance indexes for tasks and related entities.
- Implemented functions for optimized task sorting and manual progress tracking.
- Updated package.json to include migration scripts and dependencies for node-pg-migrate.
- Created README.md for migration guidelines and best practices.

worklenz-backend/migrate.json

@@ -0,0 +1,22 @@
+{
+  "migrations-dir": "database/pg-migrations",
+  "migrations-schema": "public",
+  "migrations-table": "pgmigrations",
+  "db": {
+    "user": {
+      "ENV": "DB_USER"
+    },
+    "password": {
+      "ENV": "DB_PASSWORD"
+    },
+    "host": {
+      "ENV": "DB_HOST"
+    },
+    "port": {
+      "ENV": "DB_PORT"
+    },
+    "database": {
+      "ENV": "DB_NAME"
+    }
+  }
+}