Create "Getting Started" page

[aik099]

We need to create "Getting Started" page were library usage will be described from top to bottom (with Behat and with PHPUnit):

1. installing via Composer
2. create test case (for PHPUnit)
3. writing first test that uses session (for PHPUnit)
4. configuring via .behat.yml (for Behat)
5. adding connecting QATools to your FeatureContext