[skip ci] Fixes to tutorial-performance-tuning

docs/guide-ja/structure-modules.md completed [ci skip]

Add docs/guide-ja/caching-*.md [ci skip]

[skip ci] add structure-controllers.md [UK]

Update structure-extensions.md [ci skip]

Update README.md [skip ci]

Update structure-views.md

Fixed broken link in docs

Fixed `yii\sphinx\QueryBuilder` does not support comparison operators (>,<,>= etc) in where specification

Fixes #5925: `ArrayHelper::htmlEncode()` does not work properly when the value being encoded is a nested array

You are validating the data, not users.

Recursive method call must have the same parameters as the first call.

docs/guide-ja/structure-views.md added [ci skip]

[ci skip] Serbian translations update

fixed twig example in tpl engines tutorial