Add support to CSP

There are detailed instuctions how to implement CSP in https://support.cookieinformation.com/en/articles/8282189-csp-implementa....

1. We could add a boolean checkbox in the module to enable CSP.
2. Add the needed attribute to the popup script based on the boolean value.

Rest of the stuff seems to need changes in CSP configuration and Cookie information template. These parts can be handled with readme.