[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/search.html

@@ -11,13 +11,13 @@
                     <option disabled>Reviewed Packages</option>
                 {% endif %}
                 {% for obj in reviewed_objects %}
-                    <option value="{{ obj.url }}" selected>{{ obj.name }}</option>
+                    <option value="{{ obj.url }}" selected>{{ obj.name|safe }}</option>
                 {% endfor %}
                 {% if unreviewed_objects %}
                     <option disabled>Unreviewed Packages</option>
                 {% endif %}
                 {% for obj in unreviewed_objects %}
-                    <option value="{{ obj.url }}">{{ obj.name }}</option>
+                    <option value="{{ obj.url }}">{{ obj.name|safe }}</option>
                 {% endfor %}
             </select>
         </div>