guard rail customization

[uchchwhash]

• setting guard_rail: False now turns the guard rail off
• [X] Closes #83

[codecov[bot]]

Codecov Report

Merging #95 (625fa7a) into master (b153ab0) will increase coverage by 2.15%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #95      +/-   ##
==========================================
+ Coverage   61.59%   63.75%   +2.15%     
==========================================
  Files           8        8              
  Lines         638      640       +2     
==========================================
+ Hits          393      408      +15     
+ Misses        245      232      -13     

Impacted Files	Coverage Δ
datacube_wps/processes/__init__.py	69.78% <100.00%> (+4.92%)	:arrow_up: