[WIP] extracted date format converting to a helper class

fixes #5080

Fixes #5058: Added `$pageSize` parameter to `Pagination::createUrl()` to allow creating URLs with arbitrary page sizes

Fix alias in authclient widget asset bundle

[WIP] New asset management

Fixes #4454: Improved asset bundle managed and used composer-asset-plugin to manage the dependencies on 3rd-party JS libraries

Conflicts:
	apps/basic/composer.json
	composer.json

[ci skip] Update structure-views.md

We should note that the application is the global module itself, otherwise the paragraph can hardly be understood by someone unfamiliar with yii architecture.

use "just now" for empty time difference in Formatter.

fixed wrong language name definition

adding and reworking the conversion of:
- ICU to PHP
- PHP to ICU
- ICU to JUI
- PHP to JUI

Fixes #3581: Added `yii\validators\CompareValidator::type` to support type conversion before comparing values

Fixes #5039: `UniqueValidator` and `ExistValidator` did not respect query conditions added by default scope

[skip ci] Added polish guide - README.md