chore: security markdown

[cmwylie19]

Description

• Creates a preferred method of contact by security researchers in the event of a security vulnerability instead of posting it publicly which could lead to disclosure of vulnerability details.
• Provides description of where and how to report
• When a vulnerability is reported, we can accept it, ask more questions, or reject it. If accepted, we are ready to collaborate on a fix.
• Vulnerability is less likely to be in the public eye
• Updates the docs

Related Issue

Fixes #639

Relates to #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed