[Java][Feature Request]Show app description only if flown in client opts.

Description

As per DefaultGenerator class, if the config flown by client does not have an app description, the default description is set to "No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)"
Shouldn't there be a capability to show description only if flown in config? And show nothing if there is no description in the config. The above text looks out of context in the documentation generated for an api.

Swagger-codegen version

2.2.1

Swagger declaration file content or url

https://gist.github.com/vyshnavi-pilly/cefac3a7c1fab912e09fa0bbac62b7e9

Command line used for generation

ClientOptInput clientOptInput = new ClientOptInput();
clientOptInput.setConfig(config);
new DefaultGenerator().opts(clientOptInput).generate();

Steps to reproduce

1. Input the provided json to swagger codegen
2. As there is no app level description the generated html shows the app description as "No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)"

Suggest a fix/enhancement

Here is the piece of code causing this:
if (StringUtils.isEmpty(info.getDescription())) {
// set a default description if none if provided
config.additionalProperties().put("appDescription",
"No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)");
config.additionalProperties().put("unescapedAppDescription", "No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)");
} else {
config.additionalProperties().put("appDescription", config.escapeText(info.getDescription()));
config.additionalProperties().put("unescapedAppDescription", info.getDescription());
}

Start at the DefaultGenerator logic shown in the issue and reproduce the generated HTML using the linked Swagger declaration and ClientOptInput command. Check how appDescription and unescapedAppDescription are consumed in the generated documentation. Done means an absent config description produces no default text, while a supplied description remains displayed.