Split test files

[sue445]

Context

Now, integration test files are very large....

• https://github.com/itamae-kitchen/itamae/blob/v1.10.3/spec/integration/recipes/default.rb : 558 lines
• https://github.com/itamae-kitchen/itamae/blob/v1.10.3/spec/integration/default_spec.rb : 335 lines

Future

I want to split there into multiple files.

e.g.) mitamae

• https://github.com/itamae-kitchen/mitamae/tree/v1.7.1/spec/recipes
• https://github.com/itamae-kitchen/mitamae/tree/v1.7.1/spec/integration