Refactor QA::Resource::Base class

Add ability to update existing attribute values on reload! call

Seperate class method declaration for better readability

Add attributes method for shorter multiple attribute declaration

Add init method to create new instance of class without performing
fabrication

Fix custom attribute tracking

Add reload capability to MergeRequest resource

Update id to iid to be in line with api response

Remove custom reload! overload

Add mr comments validation to github importer spec

Remove unnecessary evaluator

Remove attribute reference in initialize block

Remove unnecessary require of blank

Fix yard doc comments

Remove attribute method tracking via unused method variable

Refactor Resources to use init method instead of new.tap

Use more up to date variant of calling unbound method