Add public API factories to create BrowserDriver and BrowserStateAsserter

• Type: New Feature
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: alloy-2.0.0, alloy-3.0.0, test-selenium-0.3.1
• Fix Version/s: alloy-2.0.1, alloy-3.0.1, test-selenium-0.4.0
• Component/s: Liferay Faces Alloy / Showcase / Tests, Liferay Faces Test Selenium
• Labels: None

Currently, BrowserDriver and BrowserStateAsserter can only be created by classes that extend IntegrationTesterBase. In the rare cases where tests (like InputDateTimeMobileBrowserTester) need to use a different BrowserDriver (for mobile emulation etc.), IntegrationTesterBase unnecessarily creates a BrowserDriver that is unused by the tests. Tests which require their own instance of BrowserDriver should not extend IntegrationTesterBase, but for now they must since that is the only way to access the newBrowserDriver() and newBrowserStateAsserter() methods. This task involves extracting out those methods and creating factories for them.