selenium: Remove Jenkins configuration file

Both Mocha and Cucumber tests should run. Since WebdriverIO supports only
running one test framework, the only way to do it is to have a generic
configuration file and two framework-specific files (Mocha, Cucumber). Having
Jenkins configuration file complicates things, and there is no need for
it.

Bug: T179190
Change-Id: I710066f7b5479dcad27aa57cd61007c1c2d88931