chg: [internal] Cleanup of the pull function
chg: [internal] Cleanup of the pull function

- split into functions based on the concerns it handles
- separated event download and proposal download into separate functions

MISP/MISP,devnull-/MISP,FIRSTdotorg/MISP,Rafiot/MISP,FIRSTdotorg/MISP,MISP/MISP,SteveClement/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,devnull-/MISP,FloatingGhost/MISP,SteveClement/MISP,Rafiot/MISP,Rafiot/MISP,FloatingGhost/MISP,FIRSTdotorg/MISP,SteveClement/MISP,devnull-/MISP,MISP/MISP,devnull-/MISP,FloatingGhost/MISP,SteveClement/MISP,MISP/MISP,Rafiot/MISP,MISP/MISP,SteveClement/MISP