added project start and end date (#1303)

* added sortable js library
* activity in invoice is optional
* added javascript widget for paginated boxes
* fix activity dropdown for globals only
* added timesheet service to reduce code duplication
* use repository to query for teams in dropdowns
* added project validator
* validate project start and end against timesheet
* include begin and end in dynamic form requests for projects
* added timezone and language option to import flag, improve timesheet import speed
* deactivate cross-timezone filter
* add virtual fields to field order list
* composer update
* added param to ignore dates
* position loader icon fixed - fixes #1330
* permission problem when creating a new project - fixes #1340
* remove dev dependencies webserver and thanks bundle
* stop information leak (begin and end date) in duration mode - fixes #1307
* unify timesheet edit dialog for user and admins
* fix security issue, own rates exposed to unauthorized users in multi-update dialog

src/Voter/ProjectVoter.php

@@ -90,8 +90,13 @@ class ProjectVoter extends AbstractVoter
             }
         }
 
+        // new projects have no customer
+        if (null === ($customer = $subject->getCustomer())) {
+            return false;
+        }
+
         /** @var Team $team */
-        foreach ($subject->getCustomer()->getTeams() as $team) {
+        foreach ($customer->getTeams() as $team) {
             if ($hasTeamleadPermission && $user->isTeamleadOf($team)) {
                 return true;
             }