Adding a configuration parameter csp-options that, when set, adds a
Content-Security-Policy header to the apache configuration.
This header can prevent or minimize the risk of certain types of
security threats by placing restrictions on the things the web page's
code can do.
Closes-Bug: #2118835
Change-Id: I06f0b1c2787fa56460e5a196d3ca07c0a85c14e3
Signed-off-by: Jorge Merlino <jorge.merlino@canonical.com>