Allow creation of new or tryit notebook from iomd template

[wlach]

Partially fixes #2565, currently this is limited to creating a notebook with a specific iomd-- ideally we would also allow attaching files to the payload as well, but that will require handling these as POST requests (which is considerably more technically involved)

This also needs tests and documentation.

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

[wlach]

Put this PR on staging, here's an example of it in action: https://definitely-staging.iodide.io/tryit/?iomd=%25%25%20md%0A%0AHi%20this%20is%20a%20markdown%20cell%21%0A%0A%25%25%20js%0A%0A%2F%2F%20Oh%20hai%20this%20is%20a%20js%20cell%0Avar%20x%20%3D%20123%3B%0Ax%20%2F%203.14

[codecov]

Codecov Report

Merging #2676 into master will decrease coverage by 7.43%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #2676      +/-   ##
=========================================
- Coverage   75.64%   68.2%   -7.44%     
=========================================
  Files         234     181      -53     
  Lines        5819    4105    -1714     
  Branches      943     824     -119     
=========================================
- Hits         4402    2800    -1602     
+ Misses       1400    1305      -95     
+ Partials       17       0      -17

Impacted Files	Coverage Δ
server/openidc/tests/test_middleware.py
server/notebooks/urls.py
server/files/api_views.py
server/tests/test_settings.py
server/tests/test_token_authentication.py
server/notebooks/apps.py
server/files/serializers.py
server/notebooks/api_views.py
server/notebooks/api_urls.py
server/notebooks/middleware.py
... and 41 more

[wlach]

Added tests and changelog, I think I'm going to skip documentation of this feature for now.