[SDTEST-158] Browser tests support via selenium integration

[anmarchenko]

What does this PR do?
Automatically recognises tests that use selenium and marks them as browser tests. Integrates with Datadog RUM to automatically show browser sessions in the test run view (see screenshots below).

Additional Notes

• this PR introduces the concept of automatically instrumenting external libraries without requiring users to change configuration: Selenium should be required and configured by the time when test session starts, so I added Contrib. auto_instrument_on_session_start! method that automatically instruments it when test session starts
• it turned out not to be enough to instrument selenium-webdriver gem because capybara has its own logic to reset browser session between test runs. In this PR both Selenium::WebDriver::Driver and Capybara::Selenium::Driver (not that capybara is de-facto the default testing library for e2e tests in Ruby)

How to test the change?
Unit tests are provided.

Tested on DD staging using the following test:

require_relative "helper"

class SeleniumTest < Minitest::Test
  include Capybara::DSL
  include Capybara::Minitest::Assertions

  def teardown
    Capybara.reset_sessions!
    Capybara.use_default_driver
  end

  def test_selenium
    visit "https://dd.datad0g.com/"
    assert page.has_content?("Datadog")
  end
end

With the following results

Browser tags and is_rum_active tag:

Browser session replay connected to a test:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 95.00000% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 98.87%. Comparing base (1c997fd) to head (691bf86).
Report is 2 commits behind head on main.

Files	Patch %	Lines
lib/datadog/ci/contrib/selenium/capybara_driver.rb	65.21%	8 Missing ⚠️
lib/datadog/ci/contrib/selenium/navigation.rb	93.93%	2 Missing ⚠️
lib/datadog/ci/contrib/selenium/driver.rb	95.65%	1 Missing ⚠️
lib/datadog/ci/contrib/selenium/patcher.rb	94.44%	1 Missing ⚠️
lib/datadog/ci/contrib/selenium/rum.rb	95.23%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #183      +/-   ##
==========================================
- Coverage   98.95%   98.87%   -0.09%     
==========================================
  Files         209      220      +11     
  Lines        9758    10011     +253     
  Branches      452      465      +13     
==========================================
+ Hits         9656     9898     +242     
- Misses        102      113      +11     

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[romainkomorndatadog]

Should the script_executor be ensuring its result's a bool, rather than checking for both here?

[anmarchenko]

script_executor is coming from selenium-webdriver, it could be Selenium::WebDriver::Manager or Selenium::WebDriver::Driver

One could say that we need to be exactly sure what type this returns but in Ruby case one can never be sure. Another more beatiful way to write it would be is_rum_active_script_result.to_s == "true", I think this would look better

[romainkomorndatadog]

hehe, I would be more likely to try to cast the string to a bool :) but anyway, it's not very important, I think the code's fine as is.