Adds Content-Security-Policy template to theme (#504)

* feat: added csp.html template to theme head element

* feat: added my name to CONTRIBUTORS

* fix: added conditional logic for templating to stabilize build

* feat: Added CSP section to example config.toml

* fix: updated template logic

* updated contributors to reference website and not github

* fix conflict with contributors, moved csp out of _shared dir

Co-authored-by: Luiz F. A. de Prá <luizdepra@users.noreply.github.com>

exampleSite/config.toml

@@ -80,6 +80,25 @@ disqusShortname = "yourdiscussshortname"
 [params.cloudflare]
     token = "token"
 
+# If you want to implement a Content-Security-Policy, add this section
+[params.csp]
+	childsrc = ["'self'"]
+	fontsrc=["'self'",
+		"https://fonts.gstatic.com",
+		"https://cdn.jsdelivr.net/"]
+	formaction = ["'self'"]
+	framesrc = ["'self'"]
+	imgsrc = ["'self'"]
+	objectsrc = ["'none'"]
+	stylesrc = ["'self'",
+		"'unsafe-inline'",
+		"https://fonts.googleapis.com/",
+		"https://cdn.jsdelivr.net/"]
+	scriptsrc = ["'self'",
+		"'unsafe-inline'",
+		"https://www.google-analytics.com"]
+	prefetchsrc = ["'self'"]
+
 [taxonomies]
   category = "categories"
   series = "series"