feat: add integrations

[mpfeil]

This pull request introduces several notable changes to the schema definitions and relationships in the codebase, primarily adding new integrations and enums. The key changes are summarized below:

Schema Enhancements:

• Added a new import for deviceToIntegrations in the device schema file to establish relationships with integrations.

Relationship Additions:

• Updated deviceRelations to include a one-to-one relationship with deviceToIntegrations, linking devices to their respective integrations.

Enum Definitions:

• Introduced MqttMessageFormatEnum and TtnProfileEnum enums to support different message formats and profiles for integrations.

Integration Schema:

• Added a new file integration.ts defining the schema for mqttIntegration, ttnIntegration, and deviceToIntegrations, including their relationships and constraints.

Export Updates:

• Updated the index.ts file to export the new integration schema, making it accessible throughout the application.