more refactoring and fixing old specs

app/controllers/concerns/cycle_analytics_params.rb

...controllers/projects/cycle_analytics/events_controller.rb

app/controllers/projects/cycle_analytics_controller.rb

app/models/cycle_analytics.rb

lib/gitlab/cycle_analytics/summary.rb

spec/models/cycle_analytics/code_spec.rb

spec/models/cycle_analytics/issue_spec.rb

spec/models/cycle_analytics/plan_spec.rb

spec/models/cycle_analytics/production_spec.rb

spec/models/cycle_analytics/review_spec.rb

spec/models/cycle_analytics/staging_spec.rb

spec/models/cycle_analytics/summary_spec.rb

spec/models/cycle_analytics/test_spec.rb

spec/support/cycle_analytics_helpers/test_generation.rb