Solve Style/DateTime rubocop offenses

Details at:
  https://github.com/rubocop-hq/ruby-style-guide#date--time
  https://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Rails/Date

src/api/app/controllers/request_controller.rb

@@ -233,7 +233,7 @@ def request_command_setincident
   end
 
   def request_command_setacceptat
-    time = DateTime.parse(params[:time]) if params[:time].present?
+    time = Time.parse(params[:time]) if params[:time].present?
     @req.set_accept_at!(time)
     render_ok
   end

src/api/app/jobs/project_create_auto_cleanup_requests.rb

@@ -36,7 +36,7 @@ def autoclean_project(prj)
     begin
       attribute = prj.attribs.find_by_attrib_type_id(@cleanup_attribute.id)
       return unless attribute
-      time = DateTime.parse(attribute.values.first.value)
+      time = Time.parse(attribute.values.first.value)
       return unless time
     rescue ArgumentError
       # not parseable time

src/api/app/models/binary_release.rb

@@ -77,7 +77,7 @@ def self.update_binary_releases_via_json(repository, json, time = Time.now)
         # complete hash for new entry
         hash[:binary_releasetime] = time
         hash[:binary_buildtime] = nil
-        hash[:binary_buildtime] = DateTime.strptime(binary['buildtime'].to_s, '%s') if binary['buildtime'].present?
+        hash[:binary_buildtime] = Time.strptime(binary['buildtime'].to_s, '%s') if binary['buildtime'].present?
         hash[:binary_disturl] = binary['disturl']
         hash[:binary_supportstatus] = binary['supportstatus']
         if binary['updateinfoid']
@@ -204,7 +204,7 @@ def reset_cache
   def indentical_to?(binary_hash)
     binary_disturl == binary_hash['disturl'] &&
       binary_supportstatus == binary_hash['supportstatus'] &&
-      binary_buildtime == DateTime.strptime(binary_hash['buildtime'].to_s, '%s')
+      binary_buildtime == Time.strptime(binary_hash['buildtime'].to_s, '%s')
   end
   #### Alias of methods
 end

src/api/app/models/bs_request.rb

@@ -225,7 +225,7 @@ def self.new_from_hash(hashed)
       hashed.delete('description')
 
       str = hashed.value('accept_at')
-      request.accept_at = DateTime.parse(str) if str
+      request.accept_at = Time.parse(str) if str
       hashed.delete('accept_at')
       raise SaveError, 'Auto accept time is in the past' if request.accept_at && request.accept_at < Time.now
 
@@ -567,7 +567,7 @@ def changestate_accepted(opts)
           v = attrib.values.first if attrib
           if defined?(v) && v
             begin
-              embargo = DateTime.parse(v.value)
+              embargo = Time.parse(v.value)
               if /^\d{4}-\d\d?-\d\d?$/.match?(v.value)
                 # no time specified, allow it next day
                 embargo = embargo.tomorrow

src/api/app/models/cloud/backend/upload_job.rb

@@ -52,7 +52,7 @@ def self.all(user, options = {})
       end
 
       def created
-        Time.at(xml_object.created.to_i).to_datetime
+        Time.at(xml_object.created.to_i)
       end
       alias_method :created_at, :created