MDL-42625 behat: Make behat pacient
* When looking for texts inside the page or inside other containers we should wait until the elements are visible. * Same when expanding tree nodes. * Normalizing loops to spin() function using behat_base::TIMEOUT and behat_base::EXTENDED_TIMEOUT, leaving TIMEOUT for DOM load processes and EXTENDED_TIMEOUT for long processes that involves JS too. * Add page load waits between actions that involves reloading the page.