Fix control sidebar when not using the slide animation

[dfsmania]

This PR includes a fix to the control sidebar when using the data-controlsidebar-slide="false" option. Related to issue #3716

You can see it working on next video:

https://user-images.githubusercontent.com/63609705/119242705-98232400-bb36-11eb-92e4-d7df1fda8eea.mp4

Also index3.html demo page was modified to include that option, so it is easy to test on the future.

Alternative Solution.

Instead of changing the ControlSidebar.js, we can change style of .control-sidebar-open class in _control-sidebar.scss to add display: block !important instead of just display: block, as shown next:

// Control sidebar open state
.control-sidebar-open {
  .control-sidebar {
    display: block !important;   /* HERE */

    &,
    &::before {
      right: 0;
    }
  }

  &.control-sidebar-push,
  &.control-sidebar-push-slide {
    .content-wrapper,
    .main-footer {
      margin-right: $control-sidebar-width;
    }
  }
}

So, let me know what solution is better...

[dfsmania]

@danny007in I'm going to replace the old data-slide="true" option by data-controlsidebar-slide="true" on all the demo pages. Is that ok?

[danny007in]

@danny007in I'm going to replace the old data-slide="true" option by data-controlsidebar-slide="true" on all the demo pages. Is that ok?

No it will become braking change

[dfsmania]

But data-slide="true" won't have any effect now. The ControlSidebar.js plugin only read the option data-controlsidebar-slide. What's the sense to keep old usage on all the examples?

[dfsmania]

@danny007in I'm going to replace the old data-slide="true" option by data-controlsidebar-slide="true" on all the demo pages. Is that ok?

I have these changes ready. @REJack please tell me if these replacements are needed...