API returns 200 for non existing endpoints

[jkppr]

With the default set-up the Timesketch API returns an empty page with status code 200 for API endpoints that do not exist.

Reproduce:

• http://127.0.0.1:5000/api/v1/sketches/123456789 => Existing API endpoint but non existing sketch ID => Error 404
• http://127.0.0.1:5000/api/v1/sketchesASDF => Non existing API endpoint => Status Code 200 with empty page

Expected behaviour:

• When calling an API endpoint that does not exist I would expect an 404 error

[TedmanNguyen]

Working on this issue