Add examples and clarification to Swagger documentation

[henrietteharmse]

Describe the documentation deficiency Currently there are few related issues wrt Swagger documentation. This can be addressed more generally by updating OLS4 Swagger documentation from OLS3 documentation.

Url to existing documentation if applicable Swagger documentation: https://www.ebi.ac.uk/ols4/swagger-ui/index.html OLS3 documentation: https://www.ebi.ac.uk/ols4/ols3help Ideally the Swagger documentation should stand by itself and we should be able to get rid of the OLS3 documentation.