Fixes #2016: removed ability to declare scopes in ActiveRecord leaving it to ActiveQuery. Changed documentation accordingly.
Added note about scopes to upgrade guide
Fixed test breaks
Fixed scope method signatures
Fixed tests for elasticsearch, mongo, redis
Fixed wrong namespace
Added missing return to docs
Better phpdoc
Updated Making it IDE-friendly section in AR scopes doc
Changed IDE-specific method overrides to @method
Unit test for yii\mongodb\file\ActiveRecord fixed
Merge branch 'master'

Conflicts:
	tests/unit/data/ar/elasticsearch/Customer.php
Merge branch 'master'
Merge pull request #2025 from yiisoft/remove-ability-to-declare-scopes-in-ar

Fixes #2016: removed ability to declare scopes in ActiveRecord leaving it to ActiveQuery