[Core] Remove cucumber.options property

[mpkorstanje]

cucumber.options was used to control cucumbers execution when run through mvn test. This is no longer required with the introduction of property based runtime options in #1741. Removing cucumber.options allows CLI argument parsing to be separated from property parsing which simplifies the complexity of parsing significantly.

Additionally

• We remove --add-plugin and associated logic in RuntimeOptionsBuilder. All plugins are added by default.
• Separate calling System.exit from parsing the runtime options. Main should check if exit is required after parsing.
• Write tests that validate if the correct text is written to System.out and System.err by injecting these into CommandlineOptionsParser.

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).

Checklist:

• I've added tests for my code.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

Todo

• Check doc.cucumber.io for usages of cucumber.options.

[coveralls]

Coverage decreased (-0.07%) to 86.583% when pulling e9c3117 on core-remove-cucumber-options into 5b73489 on v6.x.x.