Update RuboCop configuration to inherit from theforeman-rubocop

- Added `theforeman-rubocop` as a development dependency in the gemspec.
- Changed the RuboCop configuration to inherit from `default.yml`
provided by `theforeman-rubocop` for better style alignment.
- Removed redundant cops as they are already included in the inherited
`defsault.yml` or not needed anymore.

.github/workflows/main.yml

@@ -16,6 +16,8 @@ jobs:
   rubocop:
     name: Rubocop
     uses: theforeman/actions/.github/workflows/rubocop.yml@v0
+    with:
+      command: bundle exec rubocop --parallel --format github
 
   test:
     name: Ruby

.rubocop.yml

@@ -1,9 +1,8 @@
 inherit_from: .rubocop_todo.yml
 
-require:
-  - rubocop-performance
-  - rubocop-rails
-  - rubocop-minitest
+inherit_gem:
+  theforeman-rubocop:
+    - default.yml
 
 AllCops:
   TargetRubyVersion: 2.7
@@ -12,26 +11,9 @@ AllCops:
     - 'node_modules/**/*'
     - 'vendor/**/*'
 
-Layout/ArgumentAlignment:
-  EnforcedStyle: with_fixed_indentation
-  IndentationWidth: 2
-
-Layout/EmptyLineAfterGuardClause:
-  Enabled: false
-
 Layout/LineLength:
   Enabled: 111 # TODO: discuss and set this
 
-Rails:
-  Enabled: true
-
-Style/Alias:
-  EnforcedStyle: prefer_alias_method
-
-# Don't enforce documentation
-Style/Documentation:
-  Enabled: false
-
 # Don't enforce frozen string literals
 Style/FrozenStringLiteralComment:
   Enabled: false