[core] Initial FeatureSet structures and definitions (#3614)

[core] Initial FeatureSet structures and definitions
Add default feature set to DefaultCodegen
Initial FeatureSet definitions for:

*  ada 
*  android 
*  apache2 
*  asciidoc 
*  aspnetcore 
*  avro 
*  bash 
*  c 
*  clojure 
*  cpp-pistache-server 
*  cpp-qt5-client 
*  cpp-qt5-qhttpengine-server 
*  cpp-restbed-server 
*  cpp-restsdk 
*  cpp-tizen 
*  csharp 
*  csharp-nancyfx 
*  csharp-netcore 
*  cwiki 
*  dart 
*  eiffel 
*  elixir 
*  elm 
*  erlang 
*  flash 
*  fsharp-functions 
*  go  Client/Server
*  graphql-nodejs-express-server 
*  graphql-schema 
*  groovy 
*  haskell 
*  haskell-http-client 
*  java 
*  jmeter 
*  kotlin 
*  kotlin vertx 
*  kotlin-server 
*  kotlin-spring 
*  lua 
*  mysql 
*  nim 
*  nodejs 
*  nodejs-express 
*  objc 
*  ocaml 
*  openapi 
*  openapi-yaml 
*  perl 
*  php 
*  php-laravel 
*  php-lumen 
*  php-silex 
*  php-slim 
*  php-symfony 
*  php-ze-ph 
*  powershell 
*  protobuf 
*  protobuf-schema 
*  python 
*  python-aiohttp 
*  python-blueplanet 
*  python-experimental 
*  r 
*  ror 
*  ruby 
*  ruby 
*  ruby-sinatra 
*  rust 
*  scala-akka 
*  scala-finch 
*  scala-gatling 
*  scala-http-client 
*  scala-lagom 
*  scala-play 
*  scalatra 
*  scalaz 
*  spring 
*  static docs 
*  swift 
*  typescript

samples/server/petstore/java-play-framework-fake-endpoints/public/openapi.json

@@ -1049,7 +1049,7 @@
         "x-accepts" : "application/json"
       },
       "post" : {
-        "description" : "Fake endpoint for testing various parameters\n假端點\n偽のエンドポイント\n가짜 엔드 포인트\n",
+        "description" : "Fake endpoint for testing various parameters\n 假端點\n 偽のエンドポイント\n 가짜 엔드 포인트",
         "operationId" : "testEndpointParameters",
         "requestBody" : {
           "content" : {
@@ -1155,7 +1155,7 @@
         "security" : [ {
           "http_basic_test" : [ ]
         } ],
-        "summary" : "Fake endpoint for testing various parameters\n假端點\n偽のエンドポイント\n가짜 엔드 포인트\n",
+        "summary" : "Fake endpoint for testing various parameters\n 假端點\n 偽のエンドポイント\n 가짜 엔드 포인트",
         "tags" : [ "fake" ],
         "x-contentType" : "application/x-www-form-urlencoded",
         "x-accepts" : "application/json"