[afs-spring-server] Replace springfox-swagger2 by springdoc

[sylvlecl]

• Do you want to request a feature or report a bug?

Technical component update.

• What is the current behavior?

Using springfox-swagger2 to generate swagger doc and integrate swagger-ui into afs-spring-server.

• What is the expected behavior?

Using springdoc to generate swagger doc and integrate swagger-ui into afs-spring-server. ?

• What is the motivation / use case for changing the behavior?

Springdoc supposed to be better maintained than springfox-swagger2.