ref(cli): Add env for pushing snuba queries to a file

[k-fish]

Summary

In local dev for debugging it might be nicer to have snuba logs pushed into a file; easier to copy and devserver is pretty spammy nowadays. This isn't set by default, we can likely leave managing the resulting log file size to the developer.

eg. usage SENTRY_SNUBA_INFO_FILE="../snuba.log" devserver

[k-fish]

@wmak just tail -f <logfile> in a new tmux pane... We can change this later if people find they're doing that 🤷

[codecov[bot]]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (a1ae836) 81.40% compared to head (2af8932) 81.40%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #65024      +/-   ##
==========================================
- Coverage   81.40%   81.40%   -0.01%     
==========================================
  Files        5251     5251              
  Lines      232145   232151       +6     
  Branches    45581    45583       +2     
==========================================
- Hits       188987   188975      -12     
- Misses      37276    37289      +13     
- Partials     5882     5887       +5     

Files	Coverage Δ
src/sentry/utils/snuba.py	89.12% <30.00%> (-0.52%)	:arrow_down:

... and 6 files with indirect coverage changes