httpextbin: Add schdeuling query handler
httpextbin: Add schdeuling query handler

Scheduling query handler is implemented.
In streaming cases, queue2 element need to be deployed in the pipeline, because
queue2 is one of the element for calcurating buffering logic.
If the source element reply scheduling query with BANDWIDTH_LIMITED flags,
then uridecodebin is going to configure queue2 element.

:issues addressed:
[BHV-11355] implement scheduling query on httpextbin

Change-Id: Ie6ccc254636f0322d72ba66cf6cb96604e300016
Reviewed-on: https://gpro.palm.com/56109
Tested-by: Wonchul Lee <9841bdbec9dbb2acc2dcaaa1dab0491399f0e464@lge.com>
Reviewed-by: Jeongseok Kim <0c03ab7a1b32f29697716389c3f9549845834271@lge.com>
Tested-by: Jeongseok Kim <0c03ab7a1b32f29697716389c3f9549845834271@lge.com>
(cherry picked from commit a73654e1591b352f0d577591ea32c327585ddba2)

justinjoy/gst-plugins-cool,justinjoy/gst-plugins-cool