refactor: Remove unnecessary debug print statements

- Removed several `println!` statements from the `governance`
  controller and `proposals` database module to improve code
  cleanliness and reduce unnecessary console output.
- Updated the `all_activities.html` template to use the
  `created_at` field instead of `timestamp` for activity dates.
- Updated the `index.html` template to use the `created_at`
  field instead of `timestamp` for activity timestamps.
- Added `#[allow(unused_assignments)]` attribute to the
  `create_activity` function in `proposals.rs` to suppress a
  potentially unnecessary warning.

actix_mvc_app/src/views/governance/all_activities.html

@@ -54,7 +54,7 @@
                                             </td>
                                             <td>
                                                 <small class="text-muted">
-                                                    {{ activity.timestamp | date(format="%Y-%m-%d %H:%M") }}
+                                                    {{ activity.created_at | date(format="%Y-%m-%d %H:%M") }}
                                                 </small>
                                             </td>
                                         </tr>

actix_mvc_app/src/views/governance/index.html

@@ -130,7 +130,7 @@
                             <div>
                                 <div class="d-flex justify-content-between align-items-center">
                                     <strong>{{ activity.user }}</strong>
-                                    <small class="text-muted">{{ activity.timestamp | date(format="%H:%M") }}</small>
+                                    <small class="text-muted">{{ activity.created_at | date(format="%H:%M") }}</small>
                                 </div>
                                 <p class="mb-1">{{ activity.action }} on <a
                                         href="/governance/proposals/{{ activity.proposal_id }}">{{