Make Datepicker translatable

Summary: This adds the Ablillity to translate the Content of the Date Picker. It is possible to display more than one Letter for the Day Captions.

Test Plan:
 - Change the Language in the User Preferences, make sure it translates 'S|M|T|W|T|F|S' and Months or add the following to the translation.override config to get German Translation:

```
{
    'S|M|T|W|T|F|S': 'So|Mo|Di|Mi|Do|Fr|Sa',
    'January': 'Januar',
    'February': 'Februar',
    'March': 'März',
    'May': 'Mai',
    'June': 'Juni',
    'July': 'Juli',
    'October': 'Oktober',
    'December': 'Dezember'
}
```
 - Open Datepicker on a Datefield (Edit Event or Edit for Custom Field of Type date)
 - The Day Headers and the Months should now be translated

Reviewers: O1 Blessed Committers, speck

Reviewed By: O1 Blessed Committers, speck

Subscribers: CSharp, 0, speck, tobiaswiese

Tags: #calendar

Differential Revision: https://we.phorge.it/D25016

resources/celerity/map.php

@@ -481,7 +481,7 @@ return array(
     'rsrc/js/core/behavior-detect-timezone.js' => '78bc5d94',
     'rsrc/js/core/behavior-device.js' => 'ac2b1e01',
     'rsrc/js/core/behavior-drag-and-drop-textarea.js' => '7ad020a5',
-    'rsrc/js/core/behavior-fancy-datepicker.js' => '956f3eeb',
+    'rsrc/js/core/behavior-fancy-datepicker.js' => 'e77fcc9d',
     'rsrc/js/core/behavior-form.js' => '55d7b788',
     'rsrc/js/core/behavior-gesture.js' => 'b58d1a2a',
     'rsrc/js/core/behavior-global-drag-and-drop.js' => '1cab0e9a',
@@ -635,7 +635,7 @@ return array(
     'javelin-behavior-editengine-reorder-configs' => '4842f137',
     'javelin-behavior-editengine-reorder-fields' => '0ad8d31f',
     'javelin-behavior-event-all-day' => '0b1bc990',
-    'javelin-behavior-fancy-datepicker' => '956f3eeb',
+    'javelin-behavior-fancy-datepicker' => 'e77fcc9d',
     'javelin-behavior-global-drag-and-drop' => '1cab0e9a',
     'javelin-behavior-harbormaster-log' => 'b347a301',
     'javelin-behavior-herald-rule-editor' => '0922e81d',
@@ -1781,13 +1781,6 @@ return array(
       'javelin-vector',
       'javelin-stratcom',
     ),
-    '956f3eeb' => array(
-      'javelin-behavior',
-      'javelin-util',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-vector',
-    ),
     '9623adc1' => array(
       'javelin-behavior',
       'javelin-stratcom',
@@ -2174,6 +2167,13 @@ return array(
       'javelin-dom',
       'phabricator-draggable-list',
     ),
+    'e77fcc9d' => array(
+      'javelin-behavior',
+      'javelin-util',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-vector',
+    ),
     'e8240b50' => array(
       'javelin-behavior',
       'javelin-stratcom',

src/view/form/control/AphrontFormDateControl.php

@@ -267,9 +267,25 @@ final class AphrontFormDateControl extends AphrontFormControl {
     $week_key = PhabricatorWeekStartDaySetting::SETTINGKEY;
     $week_start = $viewer->getUserSetting($week_key);
 
+    $date_pht = array(
+      'S|M|T|W|T|F|S' => pht('S|M|T|W|T|F|S'),
+      'January' => pht('January'),
+      'February' => pht('February'),
+      'March' => pht('March'),
+      'April' => pht('April'),
+      'May' => pht('May'),
+      'June' => pht('June'),
+      'July' => pht('July'),
+      'August' => pht('August'),
+      'September' => pht('September'),
+      'October' => pht('October'),
+      'November' => pht('November'),
+      'December' => pht('December'),
+    );
     Javelin::initBehavior('fancy-datepicker', array(
       'format' => $this->getDateFormat(),
       'weekStart' => $week_start,
+      'pht' => $date_pht,
       ));
 
     $classes = array();

webroot/rsrc/js/core/behavior-fancy-datepicker.js

@@ -13,6 +13,7 @@ JX.behavior('fancy-datepicker', function(config, statics) {
   }
   statics.initialized = true;
 
+  var pht = JX.phtize(config.pht);
   var picker;
   var anchor_node;
   var root;
@@ -262,18 +263,18 @@ JX.behavior('fancy-datepicker', function(config, statics) {
     var year = valid_date.getYear() + 1900;
 
     var months = [
-      'January',
+      pht('January'),
-      'February',
+      pht('February'),
-      'March',
+      pht('March'),
-      'April',
+      pht('April'),
-      'May',
+      pht('May'),
-      'June',
+      pht('June'),
-      'July',
+      pht('July'),
-      'August',
+      pht('August'),
-      'September',
+      pht('September'),
-      'October',
+      pht('October'),
-      'November',
+      pht('November'),
-      'December'];
+      pht('December')];
 
     var buttons = [
       cell('\u25C0', 'm:-1', false, 'lrbutton'),
@@ -330,14 +331,14 @@ JX.behavior('fancy-datepicker', function(config, statics) {
     var weeks = [];
 
     // First, render the weekday names.
-    var weekdays = 'SMTWTFS';
+    var weekdays = pht('S|M|T|W|T|F|S').split('|');
     var weekday_names = [];
     var week_start = parseInt(get_week_start(), 10);
     var week_end = weekdays.length + week_start;
 
     for (var ii = week_start; ii < week_end; ii++) {
       var index = ii%7;
-      weekday_names.push(cell(weekdays.charAt(index), null, false, 'day-name'));
+      weekday_names.push(cell(weekdays[index], null, false, 'day-name'));
     }
     weeks.push(JX.$N('tr', {}, weekday_names));