CMS 6 - Change sitetree search render default to false

[emteknetnz]

ElementSiteTreeFilterSearch.render_elements default is true - it was created this way to maintain the existing CMS 5.0 behaviour

Switching this to false creates a large boost in the cms sitetree search performance

Unless not rendering elements results in a significantly worse, the default should be changed to false for CMS 6

[maxime-rainville]

My hope is that we'll have a proper search service soon and will be bale to power site search through this instead and this card will become redundant. But my hopes have been dashed before.