Improves performance of o.j.r.junit.before.test extension.point processing. Part of #456

- adds possiblity to decide to run method runBeforeTest() only once for whole test suite
- moves extensions evaluating to RedDeerSuite class
- splits extension to this two classes CloseWelcomeScreenExt and DoNotDownloadMavenIndexesExt
- renamed o.j.r.junit.eclipseext to o.j.t.junit.extension