Sequences refactored for generating, rewinding, setting & bugfix.

:generate and :generate_list expanded to work with factory sequences:
  - generate(:sequence_name)
  - generate(:factory_name, :sequence_name)
  - generate_list(:sequence_name, 3)
  - generate_list(:factory_name, :sequence_name, 3)

:rewind_seqence added to rewind individual sequences
  - rewind_sequence(:factory_name, :trait_name, :sequence_name)

:set_sequence added to set the sequence to a new value:
  - set_sequence(:sequence_name, new_value)
  - set_sequence(:factory_name, :sequence_name, new_value)

Test coverage at 100% & docs updated.

Author: CodeMeister

spec/acceptance/sequence_setting_spec.rb

@@ -342,6 +342,7 @@
       it "fails with an unmatched Enumerable value" do
         names = %w[Jane Joe Josh Jayde John].to_enum
 
+        allow(names).to receive(:next).and_raise(StopIteration)
         allow_any_instance_of(FactoryBot::Sequence).to receive(:can_set_value_by_index?).and_return(false)
 
         FactoryBot.define do