Update mixin for lib-menu, and use it for migration

[Bellfalasch]

A lot have happened in lib-menu over the years that we could use in the migration.

• Use lib-menu 1.3.0
• Use mixin variant "windowed" (included) instead of old one.
• Migrate "show in menu" setting from CMS to XP with this (if not already).
• Migrate "open in new window" setting on URLs (other types too?) from CMS to XP.

New mixin code:

<mixin>
    <display-name>Menu settings</display-name>
    <items>
        <input type="Checkbox" name="menuItem">
            <label>Show in menu?</label>
            <help-text>Check this to include this content in the menu.</help-text>
            <occurrences minimum="0" maximum="1"/>
        </input>
        <input type="TextLine" name="menuName">
            <label>Override menu name</label>
            <help-text>Name to be used in menu, default is to use the content's DisplayName.</help-text>
            <occurrences minimum="0" maximum="1"/>
        </input>
        <input type="Checkbox" name="newWindow">
            <label>Open in new window?</label>
            <occurrences minimum="0" maximum="1"/>
        </input>
    </items>
</mixin>