Parallel RSpec Formatter

[raysathyajith]

#23

With this PR, RSpec now supports Parallel formatting
if attach_to_launch is added, Single launch will be created and following test scenarios will be attached to it.
else, multiple launches will be created.

• Created parallel_formatter.rb for Parallel Formatter in RSpec
• Updated Formatter class to re-use methods from report.rb

Command: parallel_rspec <other options> --format ReportPortal::RSpec::ParallelFormatter