Rageshake, remind user of unsupported browser and report missing features in report

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/dialogs/BugReportDialog.js

@@ -137,12 +137,20 @@ export default class BugReportDialog extends React.Component {
             );
         }
 
+        let warning;
+        if (window.Modernizr && Object.values(window.Modernizr).some(support => support === false)) {
+            warning = <p><b>
+                { _t("Your browser is unsupported, you accepted that things may not work.") }
+            </b></p>;
+        }
+
         return (
             <BaseDialog className="mx_BugReportDialog" onFinished={this._onCancel}
                     title={_t('Submit debug logs')}
                 contentId='mx_Dialog_content'
             >
                 <div className="mx_Dialog_content" id='mx_Dialog_content'>
+                    { warning }
                     <p>
                         { _t(
                             "Debug logs contain application usage data including your " +

src/rageshake/submit-rageshake.js

@@ -136,6 +136,13 @@ export default async function sendBugReport(bugReportEndpoint, opts) {
         } catch (e) {}
     }
 
+    if (window.Modernizr) {
+        const missingFeatures = Object.keys(window.Modernizr).filter(key => window.Modernizr[key] === false);
+        if (missingFeatures.length > 0) {
+            body.append("modernizr_missing_features", missingFeatures.join(", "));
+        }
+    }
+
     if (opts.sendLogs) {
         progressCallback(_t("Collecting logs"));
         const logs = await rageshake.getLogsForReport();