Use different background color as a visual indicator of correct drop target, instead of just using border

GCP-8895

Code reviewed by : Cyrus Venn Quesada
Added validation for folder name input. The following characters are no longer accepted
< > & = ;

GCP-8901

Code reviewed by Cyrus Venn Casada
Added validation for folder name input. The following characters are no longer accepted
< > & = ;

GCP-8901

Code reviewed by Cyrus Venn Casada