feat(onboarding): use .editorconfig file to get indentation style (#11456)

lib/util/json-writer/__fixtures__/.global_editorconfig

lib/util/json-writer/__fixtures__/.json_editorconfig

lib/util/json-writer/__fixtures__/.non_json_editorconfig

lib/util/json-writer/code-format.ts

lib/util/json-writer/editor-config.spec.ts

lib/util/json-writer/editor-config.ts

lib/util/json-writer/indentation-type.ts

lib/util/json-writer/index.ts

lib/util/json-writer/json-writer.spec.ts

lib/util/json-writer/json-writer.ts

lib/workers/repository/onboarding/branch/config.spec.ts

lib/workers/repository/onboarding/branch/config.ts

lib/workers/repository/onboarding/branch/create.ts

lib/workers/repository/onboarding/branch/index.spec.ts

lib/workers/repository/onboarding/branch/rebase.spec.ts

lib/workers/repository/onboarding/branch/rebase.ts

package.json

yarn.lock