Add Testing Tools to the Security Policy

[ArielSAdamsNASA]

Is your feature request related to a problem? Please describe.
Users are unaware of how cFS/elf2cfetbl is tested. By providing this information, transparency is provided to the community which promotes trust.

Describe the solution you'd like
The security policy should inform users what tools are being used to test cFS/elf2cfetbl while being cautious of liability issues. To do so, we can state explicitly that our software does not provide liability under the Apache license. The security policy should inform users that they may view the LGTM results. The policy would state that the alerts from LGTM may not be accurate, since they cannot be dismissed.

Add that security report should be emailed.

Additional context
References: https://github.com/thanos-io/thanos/security/policy

Requester Info
Ariel Adams, ASRC Federal