Add visibleCondition for block-setting icons

[Prokyonn]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
License	MIT
Documentation PR	sulu/sulu-docs#

What's in this PR?

Adds a visibleCondition to the sulu.block_setting_icon tag.

Why?

Previously the icon was only shown, when the checkbox was set to true, this condition makes it more flexible, you can now also render the icon when the checkbox is false but other conditions are true.

Example Usage

Show the icon only when the page locale is de or en and the checkbox is true.

<property name="showInAustria" type="checkbox" visibleCondition="__locale in ['de', 'en']">
        <params>
            <param name="description">
                <meta>
                    <title lang="en">This block will be visible for the Austrian .at domain</title>
                    <title lang="de">Dieser Block wird für die österreichische .at Domain sichtbar sein
                    </title>
                </meta>
            </param>
            <param name="icon" value="su-app-austria"/>
            <param name="label">
                <meta>
                    <title lang="en">Austria (.at)</title>
                    <title lang="de">Österreich (.at)</title>
                </meta>
            </param>
            <param name="skin" value="heading"/>
            <param name="type" value="toggler"/>
            <param name="default_value" value="true"/>
        </params>
        
        <tag name="sulu.block_setting_icon" icon="su-app-austria" visibleCondition="__locale in ['de', 'en'] and settings.showInAustria == true"/>
 </property>

To Do

• Create a documentation PR