Changes

Summary

1. tsk[103] adds send, accept, cancel, reject friendrequest (details)
2. tsk103 update UserEJBTest for send, accept, cancel, reject friendrequest (details)

Commit a224b3533811d216e89b1791b5ed38f5b8e122f7 by redouane tsk[103] adds send, accept, cancel, reject friendrequest
	service/src/main/java/es/uvigo/esei/dgss/letta/service/UserEJB.java
Commit e3d5057c0c71c6aa9c654b1dd87c8af0cf64685c by redouane tsk103 update UserEJBTest for send, accept, cancel, reject friendrequest
	service/src/test/java/es/uvigo/esei/dgss/letta/service/UserEJBTest.java