Fixes #2558: Enhanced support for memcached by adding `yii\caching\MemCache::persistentId` and `yii\caching\MemCache::options`

Gii `*Search` model generator fix

Http status codes are hardcoded in filter in debug

Manifest was not passed to view as was expected according to phpdoc.
We need it to extract status codes for filter.

Arbitrary http status codes are hardcoded in filter so it is impossible to search by status code not present in select.

Added support for transaction isolation levels

add translation for intro-upgrade-from-v1 [skip ci]

[ci skip]

Added ability to `yii\widgets\Menu` to encode each item's label separately

Added ability to `yii\bootstrap\Tabs` to encode each `Tabs::items['label']` separately

fixes #3220

thanks to @Ragazzo
fixes #3799

Fix translate