[kotlin][client] add tests for comma separated list in array path params (#11293)

* add tests for kotlin-array-simple-string

* add new files

* remove build fies

* clean up

samples/client/petstore/kotlin-array-simple-string/README.md

@@ -0,0 +1,49 @@
+# org.openapitools.client - Kotlin client library for Demo
+
+## Requires
+
+* Kotlin 1.4.30
+* Gradle 6.8.3
+
+## Build
+
+First, create the gradle wrapper script:
+
+```
+gradle wrapper
+```
+
+Then, run:
+
+```
+./gradlew check assemble
+```
+
+This runs all tests and packages the library.
+
+## Features/Implementation Notes
+
+* Supports JSON inputs/outputs, File inputs, and Form inputs.
+* Supports collection formats for query parameters: csv, tsv, ssv, pipes.
+* Some Kotlin and Java types are fully qualified to avoid conflicts with types defined in OpenAPI definitions.
+* Implementation of ApiClient is intended to reduce method counts, specifically to benefit Android targets.
+
+<a name="documentation-for-api-endpoints"></a>
+## Documentation for API Endpoints
+
+All URIs are relative to *http://localhost*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+*DefaultApi* | [**idsGet**](docs/DefaultApi.md#idsget) | **GET** /{ids} | 
+
+
+<a name="documentation-for-models"></a>
+## Documentation for Models
+
+
+
+<a name="documentation-for-authorization"></a>
+## Documentation for Authorization
+
+All endpoints do not require authorization.