Allow installing several modules at once in Nightwatch drupalInstallModule() function

Problem/Motivation

Now the function drupalInstallModule() accepts only one module as an argument.
But it actually works pretty slowly, because it makes a lot of actions: logs in as admin, opens the modules form, submits, confirms, logs out.

So, if a test needs to install 3 modules, it will take 3 times more time. But actually, we can just check several checkboxes on a single step instead.

Steps to reproduce

1. Execute a Nigthwatch test like this:

  browser.drupalInstall()
    .drupalInstallModule('node')
    .drupalInstallModule('media')
    .drupalInstallModule('taxonomy')
    .drupalInstallModule('layout_builder')

2. Get tired of waiting for it to end.

Proposed resolution

Allow passing an array of modules to the function drupalInstallModule() to install them at once as one workflow, like this:

  browser.drupalInstall()
    .drupalInstallModule([
      'node',
      'media',
      'taxonomy',
      'layout_builder',
    ])

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet