Use HTML beautifier to indent ERB files

We had inconsistent indentation in many places. Now we're fixing them
and adding a linter to our CI so we don't accidentally introduce
inconsistent indentations again.

app/components/admin/stats/budget_balloting_component.html.erb

@@ -30,7 +30,9 @@
 
 <table class="investment-projects-summary">
   <thead>
-    <tr><th colspan="2"><%= t("admin.stats.budget_balloting.votes_per_heading") %></th></tr>
+    <tr>
+      <th colspan="2"><%= t("admin.stats.budget_balloting.votes_per_heading") %></th>
+    </tr>
   </thead>
 
   <tbody>
@@ -49,7 +51,9 @@
 
 <table class="investment-projects-summary user-count-by-heading">
   <thead>
-    <tr><th colspan="2"><%= t("admin.stats.budget_balloting.participants_per_district") %></th></tr>
+    <tr>
+      <th colspan="2"><%= t("admin.stats.budget_balloting.participants_per_district") %></th>
+    </tr>
   </thead>
 
   <tbody>