[Filter/Main] Caps Negotiations Implemented

[Filter/Main] Caps Negotiations Implemented

It appears that the simple test case of "videosrctest --> t_converter --> t_filter --> fakesink" works up to caps-negotiations & fixating caps.

Test Case:

gst-launch-1.0 -v --gst-debug=GST_CAPS:4 --gst-plugin-path=${PATH_TO_PLUGIN} videotestsrc num-buffers=1 ! video/x-raw,format=RGB,width=280,height=40,framerate=0/1 ! videoconvert ! video/x-raw, format=BGRx ! tensor_converter silent=FALSE ! tensor_filter debug=TRUE framework='tensorflow-lite' model='./nothing' input='4:280:40' inputtype='uint8' output='1' outputtype='uint8' ! filesink location="test.bgrx.log" sync=true

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>