Security policy

[valllllll2000]

Context

We should add a security policy to the code base and to the website. See https://github.com/akvo/akvo-security/issues/2 Here is an example: https://www.google.com/.well-known/security.txt

Steps

• [ ] Add security.txt file to root folder of the codebase
• [ ] Add a security.txt to the client, ie https://uat1.akvoflow.org/.well-known/security.txt or https://uat1.akvoflow.org/security.txt