add docpage for smallbox

docs/50_Components/Smallbox.md

+## Smallbox
+
+Solid colored box to highlight a single value; optional with a link
+
+### Syntax
+
+```php
+$renderAdminLTE->getSmallbox($aOptions);
+```
+
+### Return
+
+{string} html code
+
+### Parameters
+
+* $aOptions - {array} options to describe the element
+
+Styling:
+
+Key      | Description
+---      | ---
+type     | one of [none]\|danger\|dark\|info\|primary\|secondary\|success\|warning
+shadow   | size of shadow; one of [none] (=default: between small and regular)|none|small|regular|large 
+
+Content:
+
+Key           | Description
+---           | ---
+icon          | icon css class; eg. fontawesome "far fa-thumbs-up"
+text          | visible text
+number        | Value as string, eg. to format large integers
+url           | optional: url to set a link on the bottom
+linktext      | used if a url was given: linked text
+
+### Example
+
+```php
+$renderAdminLTE->getSmallbox(array (
+  'type' => 'info',
+  'icon' => 'fas fa-shopping-cart',
+  'text' => 'New orders',
+  'number' => '150',
+  'url' => '#',
+  'linktext' => 'More info',
+))
+```