Create a weight-able model to support issuable weight
Summary
We want to consider creating a weigh-able model that would encapsulate the weight type and supporting methods given we have now extended it to:
supports_weight
and
weight_available
See: !40794 (comment 404604775)
Improvements
Move weight methods to single model.
Involved components
ee/app/models/concerns/ee/issuable.rb
ee/app/models/concerns/ee/issue.rb
ee/app/models/concerns/ee/milestone.rb
ee/app/models/concerns/ee/weight.rb