[ADF-112] Change task details feature (due date) (#2071)

* Add Assignee to readonly mode

* Style adoption and first steps to editable mode

* Switch between mode coverage

* Rebase fix

* Because of design and requirement changes, revert unnecessary parts

* Small refactoring before the introduction of CardViewDateItem

* Fix AdfCardView tests

* Editable Card date item

* Do not allow edit on task details after the task is completed.

* Update task details request

* Login footer switch fix

* Login customisable copyright text

* Card text item (first sketches)

* Small fix for supported card items' template

* Dynamic component loading for card view items

* Test and linting fixes

* Updating Readme.md

* Update Readme.md

* Fix Readme.md errors

* CardViewTextItemComponent tests

* Rebase fix

ng2-components/ng2-activiti-tasklist/src/components/activiti-task-header.component.scss

@@ -0,0 +1,24 @@
+@import 'theming';
+
+.#{$ADF} {
+    &-controls {
+        display: flex;
+        justify-content: space-between;
+    }
+
+    &-edit-controls {
+        display: flex;
+        justify-content: flex-end;
+        margin-left: auto;
+    }
+
+    &-switch-to-edit-mode,
+    &-save-edit-mode {
+        color: rgb(255, 152, 0);
+    }
+
+    &-cancel-edit-mode,
+    &-claim-controls {
+        color: rgb(131, 131, 131);
+    }
+}