✨ Separation of voting session time and bearer token lifetime (#433)

Parent issue: sequentech/meta#762

avAdmin/elections-api-service.js

@@ -350,7 +350,13 @@ angular.module('avAdmin')
             var deferred = $q.defer();
 
             var cached = electionsapi.permcache[id];
-            if (!cached) {
+            var expired = false;
+            if (cached) {
+              var decodedToken = Authmethod.decodeToken(cached);
+              var halfLife = new Date(1000*(decodedToken.create_timestamp + 0.5 * decodedToken.expiry_secs_diff));
+              expired = halfLife < Date.now();
+            }
+            if (!cached || expired) {
                 Authmethod.getPerm(
                     "edit|create|register|update|update-share|view|delete|send-auth|send-auth-all|view-results|view-stats|view-voters|view-census|start|stop|allow-tally|tally|calculate-results|publish-results|census-add|census-delete|census-delete-voted|census-activation|add-ballot-boxes|list-ballot-boxes|delete-ballot-boxes|add-tally-sheets|override-tally-sheets|list-tally-sheets|delete-tally-sheets|archive|unarchive|event-view-activity|event-receiver-view-activity|generate-auth-code|reset-voter|suspend|resume|set-public-candidates|set-authenticate-otl-period",
                     "AuthEvent",