[JAVA] Add apache httpclient library to java clients (#10218)

* Add apache java client option

* Add sample apache client config

* Switch serialization library, use time formatter

* Add pom template for apache dependencies

* Add initial implementation of ApiClient using apache

* Add apache api template

Plus switch to TypeReference to handle generic types

* Add support for sending json data

* Generate test stubs with @Ignore

* Add accept header

* Remove unnecessary builder assignments

* Set responseHeaders instance variable

* Switch to general serialize / deserialize functions

* Handle sending url encoded form data

* Split response processing into new method

* Allow requests without body

* Use general HttpResponse interface

If the method doesn't need to close it

* Use clients connection timeout

* Add constructor accepting custom client

* Handle multipart and direct file uploads

* Support file downloading

Based on the implementation in the jersey client

* Handle missing content disposition

* Raise error if body given for an unexpected method

* Use try with resources for response handling

* Remove unused url parameter encode method

* Handle content type parse exception

* Improve response content type handling

Would have had issues with content type headers containing a charset

* Make all set methods return client

* Add basic readme

* Send content type with files

* Set domain and path on cookies

Otherwise they will be excluded from the request

* Use consistent quoting in error messages

* Add generated apache sample

* Add generated docs changes

* update samples

* rename library, update samples, docs

* update readme

Co-authored-by: Harry White <hwhite@atlassian.com>

samples/client/petstore/java/apache-httpclient/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists