Enable strict content security policy

Webpack allows us to define a content security policy that utilizes
hashes to define what is, and isn't allowed to execute in the page
context.  Because we're a single page application, this means that we
can effectively defend the whole page with a few extra lines of setup.

This does not utilitize _any_ of the unsafe-* calls that content
security policy has, which should meet security standards for all uses.

Tested By:
Launched GUI, observed no functional changes, and watched console for
CSP errors.  Saw none.

Change-Id: I892df1f1b004384943be0ae6e51046054991fd45
Signed-off-by: Ed Tanous <ed.tanous@intel.com>
diff --git a/app/index.html b/app/index.html
index 62ddfc5..63ee778 100644
--- a/app/index.html
+++ b/app/index.html
@@ -2,6 +2,7 @@
 <html ng-app="app" ng-csp lang="en">
 
 <head>
+    <meta http-equiv="Content-Security-Policy" content="%%CSP_CONTENT%%">
     <meta charset="UTF-8">
     <title>OpenBMC</title>
     <meta name="viewport" content="width=device-width, initial-scale=1">