api: adds CRUD integration types and test cases

[ashwiniag]

closes #45

Introduces

• CRUD for Integration Type
• test cases
• adds OpenAPI spec
• Notes: doesn't not take care of dependent logic integrations+integrationTypes yet logic: Implement the logic for inetgrations and integrationTypes #55

As follows

Method	Endpoint	Description	cURL Command
POST
Create	/integrationtypes	Create a new integration type.	curl -X POST http://localhost:8000/api/v1/integrationtypes -H "Authorization: Bearer letsdoit" -H "Content-Type: application/json" -d '{"id": "linear", "display_name": "Linear Integration"}'
GET
Read (List)	/integrationtypes	List all integration types.	curl -X GET http://localhost:8000/api/v1/integrationtypes -H "Authorization: Bearer letsdoit" -H "Content-Type: application/json"
GET
Read (Detail)	/integrationtypes/{id}	Get details of a specific integration type.	curl -X GET http://localhost:8000/api/v1/integrationtypes/linear -H "Authorization: Bearer letsdoit" -H "Content-Type: application/json"
PUT
Update	/integrationtypes/{id}	Update an integration type by ID.	curl -X PUT http://localhost:8000/api/v1/integrationtypes/linear -H "Authorization: Bearer letsdoit" -H "Content-Type: application/json" -d '{"display_name": "Updated Linear Integration"}'

---

POST /integrationtypes

Test Case	Description	Error Handling
Valid Input	Ensure a new integration type is created successfully. ✅	response id and display_name.
Missing Required Fields	Verify error when id or display_name is not provided. ✅	400 Bad Request. ✅
Invalid ID Format	Verify error when id has invalid format (uppercase, spaces, special characters). ✅	400 Bad Request. ✅
Duplicate ID	Verify error when id already exists. ✅	409 Conflict. ✅

GET /integrationtypes/{id}

Test Case	Description	Error Handling
Valid ID	Verify response when a valid id is provided. ✅	response id and display_name.
Non-existent ID	Verify error when a non-existent id is provided. ✅	404 Not Found. ✅
Invalid ID Format	Verify error when id has invalid format (uppercase, spaces, special characters). ✅	400 Bad Request. ✅

GET /integrationtypes

Test Case	Description	Error Handling
Valid Request	Ensure all integration types are listed correctly. ✅	List of object integration types.
Empty Database	Verify response when no integration types exist. ✅	Empty list.

PUT /integrationtypes/{id}

Test Case	Description	Error Handling
Valid Update	Ensure the integration type is updated correctly with valid input. ✅	Updated response id display_name.
Invalid ID Format	Verify error when id has invalid format (uppercase, spaces, special characters). ✅	400 Bad Request. ✅
Non-existent ID	Verify error when a non-existent id is provided for update. ✅	404 Not Found. ✅
No Fields to Update	Verify error when no fields are provided in the update request. ✅	400 Bad Request. ✅