Rename directories for course 13 and 14

src/curs13/.gitkeep

src/curs13/Cursul13_Tunaru_Stefania_Emilia.md

src/curs13/arobreFQDN.png

src/curs13/grafic.png

src/curs14/.gitkeep

src/curs14/Cursul14_Tunaru_Stefania_Emilia.md

src/curs14/active.png

src/curs14/maninthemiddle.png

src/curs14/message.png

src/curs14/passive.png

src/curs14/server.png

src/curs14/sha2.png