add security policy

[naskio]

Fixes armada: Security/Security Policy - level 1 -> 4

ToDo:

• Enable private vulnerability disclosure in repository settings

[jayofdoom]

Many projects, as standard practice, have a SECURITY.md in the root of the repository. Can we symlink this one into the root (or move it there if github will recognize that)?

[tabathad]

Good call, it's best practice to place the SECURITY policy in the root of the project and add a link from the README to the security policy as well.

[naskio]

Hi @jayofdoom and @tabathad,
Thanks for pointing this out. I moved it to the project's root.

[jayofdoom]

Thanks for the update +1 LGTM