[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/delete_pathway_edge_modal.html

@@ -1,3 +1,4 @@
+
 {% load static %}
 <!-- Delete Edge -->
 <div id="delete_pathway_edge_modal" class="modal" tabindex="-1">
@@ -19,7 +20,7 @@
                             data-actions-box='true' class="form-control" data-width='100%'>
                         <option value="" disabled selected>Select Reaction to delete</option>
                         {% for e in pathway.edges %}
-                            <option value="{{ e.url }}">{{ e.edge_label.name }}</option>
+                            <option value="{{ e.url }}">{{ e.edge_label.name|safe }}</option>
                         {% endfor %}
                     </select>
                     <input type="hidden" id="hidden" name="hidden" value="delete"/>