Move security policies to summit.git

Different teams have different security policies.

Right now they are each stored in the repo of each team.

This is slightly painful and opaque since:

• Information is duplicated. Security policies are slightly different from one another.
• Someone checking the compliance can’t know what people are checking against. It’s possible but feels weird.
• There’s no list of teams who have a security policy.
• There’s no possibility of some from outside of team to review the security policy of a team.

Why don’t we move all security policies in summit.git? Everybody who has to follow such a policy would already have access to summit.git.

Feature Branch: summit.git:contrib/16893-document-security-policies

Original created by @sajolida on 16893 (Redmine)