Site deprecation warning

[wlach]

Pull Request checklist

• Documentation: If this feature has or requires documentation, the relevant docs have been updated.
• Changelog: This PR updates the changelog with any user-visible changes.
• Tests: This PR includes thorough tests or an explanation of why it does not

[codecov]

Codecov Report

Merging #3081 (67659fe) into master (2183bdc) will increase coverage by 0.42%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3081      +/-   ##
==========================================
+ Coverage   72.82%   73.25%   +0.42%     
==========================================
  Files         247      250       +3     
  Lines        6128     6292     +164     
  Branches      994     1017      +23     
==========================================
+ Hits         4463     4609     +146     
- Misses       1646     1655       +9     
- Partials       19       28       +9     

Impacted Files	Coverage Δ
server/views.py	92.85% <0.00%> (ø)
server/settings.py	84.88% <0.00%> (ø)
server/urls.py	95.45% <0.00%> (ø)