Add UsuariClient Feign client interface

Introduces UsuariClient for communication with the usuari-service using Feign. Provides methods to check if a user is granted as a user or supervisor by posting Usuari objects.

src/main/java/es/uv/saic/feign/UsuariClient.java

@@ -0,0 +1,16 @@
+package es.uv.saic.feign;
+
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+
+import es.uv.saic.domain.Usuari;
+
+@FeignClient(value = "usuari-service", url = "${saic.url.domain}")
+public interface UsuariClient {
+    @PostMapping("/grantedUser")
+    public boolean isGrantedUser(@RequestBody Usuari usuari);
+
+    @PostMapping("/grantedSupervisor")
+    public boolean isGrantedSupervisor(@RequestBody Usuari usuari);
+}