docs(security): Create SECURITY.md

[murka]

Hey, the outline-server have no SECURITY.md is not good :)

This is my proposal, and please don't forget to turn on Advisories system of Security

[murka]

@fortuna @sbruens @daniellacosse @jyyi1, what do you think about my proposal?

[daniellacosse]

We have a template for this, actually!

To report a security issue, please email [vulnerability management team alias](mailto:security@getoutline.org)
with a description of the issue, the steps you took to create the issue,
affected versions, and, if known, mitigations for the issue. Our vulnerability
management team will respond within 3 working days of your email. If the issue
is confirmed as a vulnerability, we will open a Security Advisory. This project
follows a 90 day disclosure timeline.

[daniellacosse]

We gotta use our approved SECURITY.md, see my above comment

[fortuna]

@murka Let us discuss internally and we will get back to you. We should probably bo doing this change ourselves.

I've enabled private vulnerability reporting on all the repos. Thanks for the tip.

[murka]

You're welcome, I will be await for your feedback!