[api] Remove Event::Project

`Event::Package` is a class with almost nothing that is used as
superclass for:

- `Event::CommentForProject`
- `Event::CreateProject`
- `Event::DeleteProject`
- `Event::UndeleteProject`
- `Event::UpdateProjectConfig`
- `Event::UpdateProject`

The `Event::Project` causes problem as we also have a `Project` model
in the root level. So once one of the two projects models is loaded,
Rails doens't look for the second one, which lead to uses of the wrong
model. To avoid that Rails uses the `Project` in the root level in
`Event::Project` subclasses we can call the Project specifying the
module. But for the other case there is nothing we can do. This is all
caused because we shouldn't have models with repeated names even if
they are in different levels. As the `Event::Project` is useless, we can
just remove it and add its data directly to the subclasses.

src/api/app/models/event/comment_for_project.rb

@@ -1,6 +1,8 @@
 module Event
-  class CommentForProject < Project
+  class CommentForProject < Base
     include CommentEvent
+    self.description = 'Project was touched'
+    payload_keys :project
     receiver_roles :maintainer, :watcher
     after_create_commit :send_to_bus
 

src/api/app/models/event/create_project.rb

@@ -1,7 +1,7 @@
 module Event
-  class CreateProject < Project
+  class CreateProject < Base
     self.description = 'Project is created'
-    payload_keys :sender
+    payload_keys :project, :sender
     after_create_commit :send_to_bus
 
     def self.message_bus_routing_key

src/api/app/models/event/delete_project.rb

@@ -1,7 +1,7 @@
 module Event
-  class DeleteProject < Project
+  class DeleteProject < Base
     self.description = 'Project was deleted'
-    payload_keys :comment, :requestid, :sender
+    payload_keys :project, :comment, :requestid, :sender
     after_create_commit :send_to_bus
 
     def self.message_bus_routing_key

src/api/app/models/event/undelete_project.rb

@@ -1,7 +1,7 @@
 module Event
-  class UndeleteProject < Project
+  class UndeleteProject < Base
     self.description = 'Project was undeleted'
-    payload_keys :comment, :sender
+    payload_keys :project, :comment, :sender
     after_create_commit :send_to_bus
 
     def self.message_bus_routing_key

src/api/app/models/event/update_project.rb

@@ -1,7 +1,7 @@
 module Event
-  class UpdateProject < Project
+  class UpdateProject < Base
     self.description = 'Project meta was updated'
-    payload_keys :sender
+    payload_keys :project, :sender
     after_create_commit :send_to_bus
 
     def self.message_bus_routing_key

src/api/app/models/event/update_project_config.rb

@@ -1,7 +1,7 @@
 module Event
-  class UpdateProjectConfig < Project
+  class UpdateProjectConfig < Base
     self.description = 'Project _config was updated'
-    payload_keys :sender, :files, :comment
+    payload_keys :project, :sender, :files, :comment
     after_create_commit :send_to_bus
 
     def self.message_bus_routing_key