add django-csp based on doj-crt policies

[lauraGgit]

Description

Add a CSP policy for our site. Not entirely sure how to validate this.

Additional information

using mozilla's django-csp to set a production middleware that sets the apps CSP, heaviliy leveraging the csp used on doj-crt

[codecov-commenter]

Codecov Report

Merging #1388 (c23d8d7) into main (f344996) will not change coverage.
The diff coverage is n/a.

❗ Current head c23d8d7 differs from pull request most recent head eb7d5dd. Consider uploading reports for the commit eb7d5dd to get more accurate results

@@           Coverage Diff           @@
##             main    #1388   +/-   ##
=======================================
  Coverage   90.08%   90.08%           
=======================================
  Files          51       51           
  Lines        2280     2280           
=======================================
  Hits         2054     2054           
  Misses        226      226           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f344996...eb7d5dd. Read the comment docs.

[neilmb]

Love it, thanks to packages that do just what is needed and @lauraGgit knowing how to use them.