Feature: Improve reports ui (#7032)

* Further improvements to Reports UI

- Clean up notes display
- Clean up add new note form
- Simplify controller
- Allow reopening a report with a note
- Show created at date for reports
- Fix report details table formatting

* Show history of report using Admin::ActionLog beneath the report

* Fix incorrect log message when reopening a report

* Implement fetching of all ActionLog items that could be related to the report

* Ensure adding a report_note updates the report's updated_at

* Limit Report History to actions that happened between the report being created and the report being resolved

* Fix linting issues

* Improve report history builder

Thanks @gargron for the improvements

app/javascript/styles/mastodon/admin.scss

@@ -145,6 +145,11 @@
       border: 0;
       background: transparent;
       border-bottom: 1px solid $ui-base-color;
+
+      &.section-break {
+        margin: 30px 0;
+        border-bottom: 2px solid $ui-base-lighter-color;
+      }
     }
 
     .muted-hint {
@@ -330,6 +335,36 @@
   }
 }
 
+.report-note__comment {
+  margin-bottom: 20px;
+}
+
+.report-note__form {
+  margin-bottom: 20px;
+
+  .report-note__textarea {
+    box-sizing: border-box;
+    border: 0;
+    padding: 7px 4px;
+    margin-bottom: 10px;
+    font-size: 16px;
+    color: $ui-base-color;
+    display: block;
+    width: 100%;
+    outline: 0;
+    font-family: inherit;
+    resize: vertical;
+  }
+
+  .report-note__buttons {
+    text-align: right;
+  }
+
+  .report-note__button {
+    margin: 0 0 5px 5px;
+  }
+}
+
 .batch-form-box {
   display: flex;
   flex-wrap: wrap;