Replace apivore with rswag for api tests (#969)

* Replace apivore api tests with rswag
* move to OpenAPI Spec 3.0.1
* a swagger UI is now reachable at http://localhost:3000/api-docs/index.html
*  swagger file is generated by running  `RAILS_ENV=test rails rswag`
    and it was moved from /docs/swagger.v1.yml to /swagger/v1/swagger.yml

---------

Co-authored-by: viehlieb <pf@pragma-shift.net>

.rubocop_todo.yml

@@ -451,6 +451,15 @@ RSpec/DescribedClass:
     - "spec/models/ordergroup_spec.rb"
     - "spec/models/user_spec.rb"
 
+# Offense count: 15
+# This cop supports unsafe autocorrection (--autocorrect-all).
+RSpec/EmptyExampleGroup:
+  Exclude:
+    # exclude for rswag tests:
+    - 'spec/requests/api/**/*_spec.rb'
+
+
+
 # Offense count: 65
 # Configuration parameters: CountAsOne.
 RSpec/ExampleLength:
@@ -581,6 +590,14 @@ RSpec/ScatteredSetup:
     - "spec/integration/balancing_spec.rb"
     - "spec/integration/login_spec.rb"
 
+# Offense count: 4
+# Configuration parameters: AllowedPatterns, IgnoredPatterns.
+# SupportedStyles: snake_case, camelCase
+RSpec/VariableName:
+  EnforcedStyle: snake_case
+  AllowedPatterns:
+     - ^Authorization$
+
 # Offense count: 1
 # Configuration parameters: IgnoreNameless, IgnoreSymbolicNames.
 RSpec/VerifiedDoubles: