fix: [stix export] Avoid loss of filename and md5 values in File object
fix: [stix export] Avoid loss of filename and md5 values in File object

- We take them from malware-sample value if they do not exist

FloatingGhost/MISP,SteveClement/MISP,MISP/MISP,MISP/MISP,Rafiot/MISP,MISP/MISP,MISP/MISP,SteveClement/MISP,FIRSTdotorg/MISP,FIRSTdotorg/MISP,FloatingGhost/MISP,SteveClement/MISP,SteveClement/MISP,FIRSTdotorg/MISP,Rafiot/MISP,SteveClement/MISP,Rafiot/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,Rafiot/MISP,FloatingGhost/MISP,MISP/MISP