[FEATURE] - add template layout chooser

[waldhacker1]

Usage:

Add your custom template layout select items within the plugin settings:

    TCEFORM {
        tt_content {
            pi_flexform.ke_search_pi1.view.templateLayout.addItems {
                20 = Custom search box 1
            }
        }
    }

Register your own template paths:

    plugin.tx_kesearch_pi1 {
        templateRootPaths {
            5 = EXT:your_site_package/Resources/Private/Templates/KeSearch/
        }
        partialRootPaths {
            5 = EXT:your_site_package/Resources/Private/Partials/KeSearch/
        }
    }

EXT:your_site_package/Resources/Private/Templates/KeSearch/SearchForm.html:

    <f:layout name="General"/>
    <f:section name="content">
        <f:if condition="{conf.templateLayout}">
            <f:if condition="{conf.templateLayout} == 10">
                <f:render section="defaultLayout" arguments="{_all}"/>
            </f:if>
            <f:if condition="{conf.templateLayout} == 20">
                <f:render section="customLayout" arguments="{_all}"/>
            </f:if>
        </f:if>
    </f:section>

    <f:section name="defaultLayout">
        ... default template code
    </f:section>

    <f:section name="customLayout">
        ... custom template code
    </f:section>