CSP: adjust configuration to fix errors on /series/add page.

Addressed to #226

Author: php-coder

src/main/java/ru/mystamps/web/support/spring/security/SecurityConfig.java

@@ -122,7 +122,10 @@ protected void configure(HttpSecurity http) throws Exception {
 					"default-src 'none'; "
 					// 'self' is required for: our own CSS files
 					// 'https://cdn.rawgit.com' is required for: languages.min.css (TODO: GH #246)
-					+ "style-src 'self' https://cdn.rawgit.com; "
+					// 'sha256-Dpm...' is required for: 'box-shadow: none; border: 0px;' inline CSS
+					// that are using on /series/add and /series/{id} pages.
+					+ "style-src 'self' https://cdn.rawgit.com "
+						+ "'sha256-DpmxvnMJIlwkpmmAANZYNzmyfnX2PQCBDO4CB2BFjzU='; "
 					// 'self' is required for: our own JS files
 					// 'unsafe-inline' is required for: jquery.min.js (that is using code inside of
 					// event handlers. We can't use hashing algorithms because they aren't supported
@@ -131,6 +134,8 @@ protected void configure(HttpSecurity http) throws Exception {
 					// https://github.com/jquery/jquery/blob/d71f6a53927ad02d/jquery.js#L1441-L1447
 					// and https://w3c.github.io/webappsec-csp/#unsafe-hashed-attributes-usage)
 					+ "script-src 'self' 'unsafe-inline'; "
+					// 'self' is required for: AJAX requests from our scripts (country suggestions)
+					+ "connect-src 'self'; "
 					// 'self' is required for: uploaded images and its previews
 					// 'https://cdn.rawgit.com' is required for: languages.png (TODO: GH #246)
 					// 'https://raw.githubusercontent.com' is required for: languages.png