Use static methods in page objects

[joaquimvila]

Is your feature request related to a problem? Please describe.
BasePage class for this library requires consumers to create an instance of each page object that each test uses. That adds some boilerplate code on each test that could be avoided by use of the instance.

Describe the solution you'd like
Another base page class (i.e StaticBasePage) that provides similar methods as BasePage (byCSS, byId, allByCSS, ...), but all static. Thus, they all rely on a page ElementFinder provided by a protected abstract method.

This new pattern should be the one recommended by CSW guidelines about e2e tests. Consider removing the old BasePage in further versions of the library.