SplitButton | new input properties

[cetincakiroglu]

New input properties will be added to the splitButton.

• severity
• outlined
• plain
• raised
• size
• text

Use of styleClass to assign outline, severity will no longer supported.

<p-splitButton 
      label="Secondary" 
      [model]="this.items" 
      (onClick)="save('info')" 
      styleClass="p-button-outlined p-button-secondary mr-2 mb-2"
></p-splitButton>

Instead of styleClass, users should now use related input properties to enable these features.

<p-splitButton 
      label="Secondary" 
      [model]="this.items" 
      (onClick)="save('info')" 
      outlined 
      severity="secondary"
></p-splitButton>