Stix import refactored

[davidonzo]

Main changes: The code has been refactored defining a dedicated function for the following objects:

• File objects: buildFileAttribute
• Address objects: buildAddressAttribute
• Email objects: buildEmailMessageAttribute
• Domain object: buildDomainNameAttribute
• Hostname object: buildHostnameAttribute
• URI object: buildURIAttribute

I think some function definition can be compacted in a single function, but I thing this way should be better to code management's purpose.

All objects listed below now support the "Related_Objects" import, but just for the first level.

Minor changes:

• Added support for SHA512 hash
• Added support for file_extension using the attribute type "pattern-in-file" because MISP seems to not have a specific object

Hope this help and of course I hope to have some usefull suggestion, as usually happened.

Thanks for your time in advance.

[FloatingGhost]

aaaaaaaaaaa I'm getting spammed with emails simply saying "OK" pl0x stop

[davidonzo]

Thank you very much for your time! I'll apply necessary changes ASAP and will open e new pull request, as last time. Are you agree?

Related objects are something terrible, but I need to find a way to import at least the first level.

I'm working on a new function able to parse recursively all related objects without cause e DoS to MISP. But first I need to know if this code is ok for you.

PS: sorry for to much "ok", next time I'll pay more attention :)