Add stricter CSPs

* Deprecate our default CSP
* Add strict CSP that is always our strictest setting
* Add strict eval CSP (disable unsafe-eval)
* Add strict inline CSP (disables inline styles)

This is just to move forward and have a incremental improvement of our
CSP

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>