Added awesome list of threat intelligence to README.md

[referefref]

Added awesome list of threat intelligence under General

[https://github.com/hslatman/awesome-threat-intelligence]

[This is a list of cyber threat intelligence sources, platforms, methodologies and standards]

By submitting this pull request I confirm I've read and complied with the below requirements.

Failure to properly do so will just result in the pull request being closed and everyone's time wasted. Please read it twice. Most people miss many things.

• [x] I have read and understood the contribution guidelines.
• [x] This pull request has a descriptive title. For example, Add [Name of List], not Update readme.md or Add an awesome list.
• [x] The list I added has been around for at least 20 days,
• [x] The list I added is a non-generated Markdown file in a GitHub repo,
• [x] The list I added is not a duplicate

[checkbot]

	3 Errors
:no_entry_sign:	Please check PR guidelines and check the boxes.
:no_entry_sign:	Please replace [Insert URL to the list here.] with the URL to the list.
:no_entry_sign:	Please replace [Explain what this list is about and why it should be included here.] with an explanation of why we should include this list.

	1 Message
:book:	Hi @referefref thank you for your submission at Awesome-Awesomeness. Be sure that you haven't got any errors below this. For any questions, ping @m1guelpf

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