Version 0.7.2 updates

[jshcodes]

• Moves duplicate handling to leverage the PyMISP native solution. Closes #129. Closes #67.
  • All indicator attributes have been moved to flat attributes as opposed to object attributes.
• Removes sightings integration.
• Aligns all adversary (actors) to the MISP Threat Actor galaxy. CrowdStrike only actors are created and imported to this galaxy as part of this process.
  • These actors are removed when performing a delete.
• Refactors taxonomic tagging to reduce the number of updates performed per attribute (indicator).
• Refines indicator type and malware family events and reduces the amount of time to import. Closes #118. Closes #102.
• Refines and expands Galaxy searches in an attempt to properly tag malware family indicators to the appropriate galaxy. Closes #134.
• Adds a new parameter to the configuration file to allow developers to limit the date range for Malware Family event lookups. Closes #136.

[!IMPORTANT] Due to taxonomic tagging changes, developers wanting to completely reimport data should remove all CrowdStrike data from their MISP instance (--obliterate or -ci -cr -ca) using the previous version before upgrading to the latest version and running a new import.