Use scenario disabler from within plugin

See https://github.com/finnlabs/openproject-costs/pull/184

features/issues/time_entries.feature

@@ -57,14 +57,12 @@ Feature: Tracking Time
 
   @javascript
   Scenario: Adding a time entry
-    Given the plugin openproject_costs is not loaded
     When I log 2 hours with the comment "test"
     Then I should see a time entry with 2 hours and comment "test"
     And I should see a total spent time of 6 hours
 
   @javascript @selenium
   Scenario: Editing a time entry
-    Given the plugin openproject_costs is not loaded
     When I update the first time entry with 4 hours and the comment "updated test"
     Then I should see a time entry with 4 hours and comment "updated test"
     And I should see a total spent time of 4 hours

features/step_definitions/general_steps.rb

@@ -99,20 +99,6 @@ Then /^the project "([^"]*)" is( not)? public$/ do |project_name, negation|
   p.update_attribute(:is_public, !negation)
 end
 
-Given /^the plugin (.+) is loaded$/ do |plugin_name|
-  plugin_name = plugin_name.gsub("\"", '')
-  Redmine::Plugin.all.detect { |x|
-    x.id == plugin_name.to_sym
-  }.present? ? nil : pending("Plugin #{plugin_name} not loaded")
-end
-
-Given /^the plugin (.+) is not loaded$/ do |plugin_name|
-  plugin_name = plugin_name.gsub("\"", '')
-  Redmine::Plugin.all.detect { |x|
-    x.id == plugin_name.to_sym
-  }.present? ? pending("Plugin #{plugin_name} not loaded") : nil
-end
-
 Given /^(?:the )?[pP]roject "([^\"]*)" uses the following [mM]odules:$/ do |project, table|
   p = Project.find_by(name: project)