toolbar UI updates

Revert "Added `yii\base\Module::getParam($name, $defaultValue = null)`  to conveniently work with application parameters"

This reverts commit 3b95aa9c.

Improvements in exhibition of the changed files in Gii.

Added `yii\base\Module::getParam($name, $defaultValue = null)`  to conveniently work with application parameters

Moved most of the user-related logic into form models

fixed i18n link

Adding support for the X-HTTP-Method-Override header

This reverts commit 80be824f.

This reverts commit b82a9b1c.

added home icon
removed separators with summary sections to make browsing with the panel more intuitive
updated version number display, now also shown as label

Fixes #1812: Hide potential warning message due to race condition occurring to `Session::regenerateID()` call