Make group entities display correctly without groups plugin enabled

[brettp]

Elgg's extensible architecture means there is no reason to use is_plugin_enabled() in logic anywhere in core to determine output or behavior.

[brettp]

There are only a few of these left in core itself. Core plugins (especially the tabbed profile) have tons of them.

[cash]

• admin/overview/online view
• admin/users/online view
• admin/users/newest view
• input_livesearch_page_handler()
• thewire has some that can be pulled out
• sitepages has a reference to riverdashboard that can probably be removed

[cash]

I think these have all been removed. Reopen or create new ticket if any are found.

[ewinslow]

Livesearch handler in engine/lib/input.php:311-314

// don't return results if groups aren't enabled.
if (!elgg_is_active_plugin('groups')) {
    continue;
}

[ewinslow]

Also see #3689

[brettp]

Groups is a problem because it's a top level type but the UI layer is wrapped in a plugin. We solved a similar problem with users / profile for 1.8 by adding to core the basics for users to display without the profile plugin. We could use a similar approach for groups.

[brettp]

This looks like it was fixed at some point.