Fixes #4607: AR model will throw an exception if it does not have a primary key to avoid updating/deleting data massively

Updated yii.activeform.js to use the encode option introduced in #4122.
Updated ActiveForm with new option encodeErrorSummary

fixes #4690, close #4691

[ci skip]

Fix #4630: automatic generating of unique slug value to `yii\behaviors\Sluggable`

issue #4687

You can now customize test config without having uncommitted changes in
git.

issue #4687

Created ArrayCache class

[ci skip] Docs guide russian translation: translated rest-authentication.md into Russian

Fixes #4586: Signed bigint and unsigned int will be converted into integers when they are loaded from DB by AR

Conflicts:
	framework/CHANGELOG.md

also fixed an issue with default value loading of bool columns.

fixes #3489, fixes #4085, fixes #3920
related to #4672

fixes #4654

close #4655

`$config` can now be a closure that will have the `$configInstance` passed as the first param.

updated docs.

close #4656

Fixes #4122: `Html::error()` and `Html::errorSummary()` are now accepting `encode` option. If set to false it prevents encoding of error messages

- can be used to enable caching in a request without the need for any storage
- useful for example in complex console tasks that should still be independed