feat(redis-cache): add module (#469)

[jlemesh]

Add redis-cache extra to be used in reana-workflow-controller API to cache workflow/job logs.

It will be possible to install it on demand as not all components need it. To use it, add annotation to a function, example in docs.

Also add myself to AUTHORS.md.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.

Project coverage is 34.70%. Comparing base (273b72d) to head (9a86a1b).
Report is 19 commits behind head on master.

Files with missing lines	Patch %	Lines
reana_commons/redis_cache.py	0.00%	5 Missing ⚠️
reana_commons/config.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #469      +/-   ##
==========================================
- Coverage   34.84%   34.70%   -0.15%     
==========================================
  Files          26       27       +1     
  Lines        1650     1657       +7     
==========================================
  Hits          575      575              
- Misses       1075     1082       +7     

Files with missing lines	Coverage Δ
reana_commons/config.py	0.00% <0.00%> (ø)
reana_commons/redis_cache.py	0.00% <0.00%> (ø)

[jlemesh]

Better put it to reana-workflow-controller.