Fix FP S3776 (cognitive-complexity): Ignore nested functions and default values

[ilia-kebets-sonarsource]

We wish to ignore:

1. JavaScript's old way of default value declaration = parameter || literal:
   1. at declaration
   2. in assignment
2. internal functions

[yassin-kammoun-sonarsource]

@ericmorand-sonarsource The PR is in another repository: eslint-plugin-sonarjs.