Feature/1543/merge flattened excluded in search panel (#1608)

* Change icon for flatten in nodeContextMenu #1543

* Add flatten png #1543

* merge flatten and exclude in searchpanel #1543

* Add tooltip #1543

* Update changelog #1543

* Change icon for flatten in matchingFilesCounter #1543

* Update CHANGELOG.md

* Update visualization/app/codeCharta/ui/searchPanelModeSelector/searchPanelModeSelector.component.html

Co-authored-by: Ruben Bridgewater <ruben@bridgewater.de>

* Apply code formating #1543

Co-authored-by: mehdi hambli <74670211+Med-H@users.noreply.github.com>
Co-authored-by: Ruben Bridgewater <ruben@bridgewater.de>
Co-authored-by: Cedrik Bormann <26900540+ce-bo@users.noreply.github.com>
Co-authored-by: Cedrik Bormann <cedrikbormann@gmail.com>