* Add CSP Support and enable it initially for Login page
* Update README
* Make sure that CSP is not enabled if CSP_POLICY isnt set
* Add a new value for x-csp header that tells if instance has opted-in to CSP or not
* Add more src to CSP
* Fix typo in header name
* Remove duplicate headers fn
* Add https://eu.ui-avatars.com/api/
* Add CSP_POLICY to env.example