Remove Apache license from API client generators (#4197)

* remove php apache license

* remove apache license from C#

* remove apache license in objc code

* remove license from swift 3 code

* remove apache license from perl code

* remove license from scala code

* remove license from ts, go, android, cpp, scala

* remove license from java api client

* restore clojure petstore files

* remove license from travis file

* clean up apache-related terms in php, ruby, python mustache tempaltes

* remove license from JS API cilent

samples/client/petstore/perl/t/HasOnlyReadOnlyTest.t

@@ -1,45 +0,0 @@
-=begin comment
-
-Swagger Petstore
-
-This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
-
-OpenAPI spec version: 1.0.0
-Contact: apiteam@swagger.io
-Generated by: https://github.com/swagger-api/swagger-codegen.git
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-
-=end comment
-
-=cut
-
-#
-# NOTE: This class is auto generated by the Swagger Codegen
-# Please update the test cases below to test the model.
-# Ref: https://github.com/swagger-api/swagger-codegen
-#
-use Test::More tests => 2;
-use Test::Exception;
-
-use lib 'lib';
-use strict;
-use warnings;
-
-
-use_ok('WWW::SwaggerClient::Object::HasOnlyReadOnly');
-
-my $instance = WWW::SwaggerClient::Object::HasOnlyReadOnly->new();
-
-isa_ok($instance, 'WWW::SwaggerClient::Object::HasOnlyReadOnly');
-