Adjust margins on home page, globally fix hr elements to default to having margins, and add class for hr elements to span full width of their container

templates/portfolios/fragments/add_new_portfolio_member.html

@@ -16,7 +16,7 @@
 {% endmacro %}
 
 {% set step_one %}
-  <hr>
+  <hr class="full-width">
   <h1>Invite new portfolio member</h1>
   <div class='form-row'>
     <div class='form-col form-col--half'>
@@ -52,7 +52,7 @@
   </div>
 {% endset %}
 {% set step_two %}
-  <hr>
+  <hr class="full-width">
   <h1>Assign member permissions</h1>
   <a class='icon-link'>
     {{ Icon('info') }}

templates/portfolios/fragments/change_ppoc.html

@@ -5,7 +5,7 @@
 {% from "components/options_input.html" import OptionsInput %}
 
 {% set step_one %}
-  <hr>
+  <hr class="full-width">
   <h1>{{ "fragments.ppoc.update_ppoc_title" | translate }}</h1>
 
   {{
@@ -42,7 +42,7 @@
 {% endset %}
 
 {% set step_two %}
-  <hr>
+  <hr class="full-width">
   <h1>{{ "fragments.ppoc.update_ppoc_confirmation_title" | translate }}</h1>
 
   {{