Add alter hook for links generated by Extra Links deriver

Adds hook_admin_toolbar_extra_links_alter()

I would very much appreciate this addition. The ExtraLinks class unfortunately adds some links which are unncessary and duplicate, and I haven't found a built-in way to remove them.

It works with the patch #2 and a hook like this:

/**
* Implements hook_admin_toolbar_extra_links_alter().
*/
function mymodule_admin_toolbar_extra_links_alter(&$links): void {
unset($links['media_library']);
}

I guess for this to be merged we need a test, right?

Prashant.c → made their first commit to this issue’s fork.

Thanks @alieffring and @Ammaletu.
Pushed the code by creating a issue fork, some documentation work is required in admin_toolbar_tools/admin_toolbar_tools.api.php .

I corrected the doc block in the api file. There is currently only one test in this module, so I'll be bold here and set this to "needs review". :-)