Added multi app (frontend/backend) support. (mdmsoft#309)

* - Added multi app (frontend/backend) support.

* Bugfix

* Bugfix: Expanded cache key by Yii::$app->id to differenciate between apps (frontend/backend).
I did not notice, that $module->getUniqueId() returns an empty string when $module is the app itself. Therefore the cache could not differenciate between frontend and backend. Thus resulting in the same routes for all indicated apps.

* Filter out empty parent items. Sometimes a menu item is defined by url = # and is used as a container for sub-items. If all the subitems are forbidden then this patch removes the parent entry as well.

* Bugfix: Debug bar disappeared. Thanks to yongtiger (see mdmsoft#309 (comment))

Merge pull request mdmsoft#268 from cgernert/patch-2

Save new password, instead of saving the old one again

Allow directly attach rule using rule class name

docs

readme

fix assignment view

Merge pull request mdmsoft#210 from softark/add-extra-fields

Small enhancements on the Assignment pages

prepare new release depend on new `deesoft/yii2-angular` ext.

Prepare new release

bug fix