Add support for @ApiImplicitParams at class level

[JamieMagee]

This builds upon #1925, and allows for @ApiImplicitParams at class level, as well as meta-annotations which use @ApiImplicitParams at class level. For example (adapted from #1867) :

@Retention(value = RetentionPolicy.RUNTIME)
@ApiImplicitParams({@ApiImplicitParam(name = "x-my-custom-auth-header-that-keeps-repeating", required = true, dataType = "string", paramType = "header",defaultValue = "SOME_TEST_TOKEN_VALUE")})
public @interface MySwaggerImplicitSecurityHeader { }

@Api(value = "lots of API endpoints here...")
@MySwaggerImplicitSecurityHeader
public class LotsOfMethodsController {

  @ApiOperation(value = "Method1")
  public void ApiMethod1(){}

  @ApiOperation(value = "Method2")
  public void ApiMethod2(){}

  //...with more of these ApiMethods down the line

}