design: add api tag
design: add api tag

We want to find metadata based on the API it implements and based on the
specific implementation.

cfoch/gstreamer,lovebug356/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,surround-io/gstreamer,lubosz/gstreamer,cfoch/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,surround-io/gstreamer,ensonic/gstreamer,krichter722/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,surround-io/gstreamer,Lachann/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,surround-io/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,justinjoy/gstreamer,lubosz/gstreamer,cablelabs/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,centricular/gstreamer,Lachann/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,lubosz/gstreamer,centricular/gstreamer,krichter722/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,lubosz/gstreamer,lubosz/gstreamer,krichter722/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,krieger-od/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,ensonic/gstreamer,collects/gstreamer,krieger-od/gstreamer,centricular/gstreamer,krichter722/gstreamer,Lachann/gstreamer,collects/gstreamer,collects/gstreamer,justinjoy/gstreamer,collects/gstreamer,justinjoy/gstreamer,mparis/gstreamer,mparis/gstreamer,collects/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer