Designer - Rename actions options to meaningful names

Currently, users don't understand the difference between actions and operations in Designer
=> They end up creating an action, then a custom element, when they just want a simple button
=> JSF UI users end up creating actions because they are used to the old "user actions" naming.

We want to rename these options to something more meaningful to help with this problem.

TODO
In Designer

• Rename "actions" menu to "buttons"
• Rename "operation" to "button"
• Rename "action" to "custom button"
• Replace "button" icon to something more meaningful
• When clicking on + icon in actions, use the premade option
• Show label next to icon (not only for actions but all options)

Update help in actions page
Create buttons and select where to place them in the user interface.

• Button:
  Configure a button and attach an automation operation, chain or script to it.

• Custom button:
  Use code to create your custom element and bind it to a button. A typical example is displaying a confirmation dialog that will execute specific logic.

(for contextual help the simplest option needs to be shown on top so that people see it first, seen with gab)

IMPORTANT - UX IMPACTS AFFECTING OTHER SCREENS

• Show label next to icon whenever + button is used
• Icon for custom option should be used also for other places where we define a custom element: tabs page, left menu item page, main menu pages page.