close #6099

Fixes #4643: Extra options specified in `yii\widgets\Breadcrumbs::links` will be treated as HTML attributes for the generated hyperlinks

return value would not be a valid array when json encoded after unlink().

fixes #6065

Fixes #6049: `yii\db\Connection::getSchema()` for Oracle should return false when the table does not exist. Oracle does not support `ON UPDATE` clause.

Fix batchInsert bug in oci. default batchInsert sql is ``` insert into tableName(col1, col2, col3...) value(`col11`, `col12`,`col13`.... ),(`col21`, `col22`,`col23`.... ); ``` which is illegal in oracle db. Change it to ``` insert into tableName(col1, col2, col3...) select 'col11', 'col12', 'col13' from dual union select 'col21', 'col22', 'col23' from dual union select 'col31', 'col32', 'col33' from dual; ```

oracle db doesn't support `ON UPDATE` in FOREIGN KEY. remove `ON UPDATE` section in method `addForeignKey`.

fix oci bugs: \yii\db\oci\Schema::findColumns($table) return true when table doesn't exist When table doesn't exist, query in method `findColumns` return empty array instead of throw a exception.

thanks to @pana1990

close #6060

Use case:

```
    echo GridView::widget([
        ...
        'columns' => [
            ...
            [
                'attribute' => 'created_at',
                'label' => '<span data-toggle="tooltip" class="glyphicon glyphicon-time" title="'.Yii::t('app', 'Created At').'"></span>',
                'encodeLabel' => false,
                ...
            ],
```

Some Annotation Typos

close #6029

Fixes #5799: `yii\bootstrap\ButtonGroup::buttons` can take all options that are supported by `yii\bootstrap\Button`

Fixes #6018: When setting the `encode` option via `yii\widgets\ActiveRecord::errorOptions`, it works the other way around [skip ci]

Fixes #5863: Selecting all individual `yii\grid\CheckboxColumn` checkboxes in grid view wasn't resulting in "all" checkbox selected

Fixes #5688: Added optional `$formName` to `Model::loadMultiple()` to support customizing form name directly

Fixes #5768: When setting `data-confirm` attribute to a submit button, clicking on the button would not trigger form submission

Fixes #4889: Application was getting into redirect loop when user wasn't allowed accessing login page. Now shows 403