#625 Drop dependency to jinja2

[SebCorbin]

Closes #625

[codecov]

Codecov Report

Merging #627 (a74fcb2) into master (843c898) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #627      +/-   ##
==========================================
+ Coverage   86.31%   86.40%   +0.09%     
==========================================
  Files          52       52              
  Lines        2090     2104      +14     
==========================================
+ Hits         1804     1818      +14     
  Misses        286      286              

Impacted Files	Coverage Δ
silk/code_generation/curl.py	47.22% <100.00%> (ø)
silk/code_generation/django_test_client.py	72.00% <100.00%> (+2.43%)	⬆️
silk/views/sql_detail.py	95.38% <0.00%> (+1.04%)	⬆️

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