增加es埋点，优化es搜索

[liangliangyy]

No description provided.

[codecov]

Codecov Report

Merging #249 into master will increase coverage by 1.68%.
The diff coverage is 53.33%.

@@            Coverage Diff             @@
##           master     #249      +/-   ##
==========================================
+ Coverage   79.24%   80.93%   +1.69%     
==========================================
  Files          51       51              
  Lines        1995     2004       +9     
==========================================
+ Hits         1581     1622      +41     
+ Misses        414      382      -32

Impacted Files	Coverage Δ
blog/search_indexes.py	90% <ø> (-0.91%)	⬇️
DjangoBlog/elasticsearch_backend.py	0% <0%> (ø)	⬆️
blog/models.py	94.21% <100%> (+0.12%)	⬆️
blog/middleware.py	79.16% <42.85%> (-14.96%)	⬇️
blog/documents.py	70.96% <68.96%> (+70.96%)	⬆️
owntracks/views.py	85.18% <0%> (-11.12%)	⬇️

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[coveralls]

Coverage increased (+1.7%) to 80.938% when pulling 9bf363e on es into 914ac04 on master.