Simplify KHamburgerMenu menu items

Changes:

• Rename "For %d more actions:" to just "More"
• Rename "Menu-Exclusive Actions" to "More Actions"
• "Show Menubar" is shown as "Show Menubar with All Actions" when in the hamburger menu.
• "Help" menu item now has an icon (help-contents).
• "More" menu item with the menu-exclusive actions now has an icon (view-more-symbolic).
• Move "Help" menu above "More".