Prevent certificates overwriting during export

[lukaszgi]

Certificates exported using certutil have a specific file name format, independent of their content. During exports from different stores, files are overwritten because they share the same names. I propose creating separate folders for each store. The conversion between certificate formats will search for files in nested folders.

[lukaszgi]

Hi @g-bougard I commit changes proposed by you. I dont know perl so i prepared my fix basing on tutorials. After that change I tested glpi-agent and works correctly.