[Fix] Mitigate XSS attack vector by cleaning input before it hits our Database (#171)

## Changes

- All text input fields are now cleaned with nh3 to remove html tags. We allow certain html tags under `settings.py/ALLOWED_HTML_TAGS` so we can easily update the tags we allow in the future.
- All names and descriptions now use the template tag `nh_safe` in all html files.
- Usernames and emails are a small exception and are not allowed any html tags

Co-authored-by: Liam Brydon <62733830+MyCreativityOutlet@users.noreply.github.com>
Co-authored-by: jebus <lorsbach@envipath.com>
Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#171
Reviewed-by: jebus <lorsbach@envipath.com>
Co-authored-by: liambrydon <lbry121@aucklanduni.ac.nz>
Co-committed-by: liambrydon <lbry121@aucklanduni.ac.nz>

templates/modals/objects/generic_set_scenario_modal.html

@@ -1,3 +1,4 @@
+
 {% load static %}
 <div class="modal fade bs-modal-lg" id="set_scenario_modal" tabindex="-1" aria-labelledby="set_scenario_modal"
      aria-modal="true" role="dialog">
@@ -7,7 +8,7 @@
                 <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                     <span aria-hidden="true">×</span>
                 </button>
-                <h4 class="modal-title">Set Scenarios for {{ current_object.name }}</h4>
+                <h4 class="modal-title">Set Scenarios for {{ current_object.name|safe }}</h4>
             </div>
             <div class="modal-body">
                 <div id="loading_scenario_div" class="text-center"></div>