Add MapValue method to Result

[yonesko]

Convenient method to map only value ignoring error

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 75.06%. Comparing base (f209056) to head (8cdbad0).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #71      +/-   ##
==========================================
+ Coverage   74.98%   75.06%   +0.08%     
==========================================
  Files          16       16              
  Lines        1435     1440       +5     
==========================================
+ Hits         1076     1081       +5     
  Misses        336      336              
  Partials       23       23              

Flag	Coverage Δ
unittests	75.06% <100.00%> (+0.08%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[yonesko]

Merge please?