Support declarative definition of components renderers in XML

[glebfox]

Components like DataGrid, ComboBox, VirtualList support renderers to change visual appearance of their columns/list. Currently, renderer can be defined only in Controller code.

It'd be convenient to be able to define renderer in XML. One of the options is to create a composite component and use it as a renderer in XML.

Related issues: https://github.com/jmix-framework/jmix/issues/2707 https://github.com/jmix-framework/jmix/issues/841

[glebfox]

• Support fragment as a renderer content
• Data binding (including provided containers)

[KremnevDmitry]

Idea to implement in the next iteration

Custom renderer markup in XML:

<virtualList itemsContainer="usersDc">
    <renderer>
        <vbox>
            <button id="rendererButton"/>
            <textField property="username"/>
        </vbox>
    </renderer>
</virtualList>

Declarative handlers for components inside:

    @Supply(to = "virtualList.@renderer.rendererButton", subject = "clickListener")
    public ComponentEventListener<ClickEvent<JmixButton>> onRendererButtonClick(User item) {
        return clickEvent -> {
            item.doSomething();
        };
    }

[SergeiAksenov2]

Tested on: Jmix version: 2.4.999-SNAPSHOT Jmix Studio plugin version: 2.4.SNAPSHOT6859-242