v2.6.0 support for JUnit 5

Serenity 2.6.0 is a major update that adds beta support for JUnit5.

• In comparison with the JUnit4 integration, for JUnit5 tests no additional annotation is needed.
  Short overview of supported features/annotations
• Tagging : @Tag("type:name") - mvn clean verify -Dtags="type:name"
• Data Driven tests: @ParameterizedTest,@ValueSource,@EnumSource,@CsvFileSource
• Nested tests: @Nested
• @DisplayName for methods

The following plugins must be upgraded to the version 3.0.0-M5

• maven-surefire-plugin
• maven-failsafe-plugin

A big callout to @cliviu who spearheaded this module!