doc: Add Google Summer of Code ideas list
doc: Add Google Summer of Code ideas list

GSoC requires a link to our ideas list. Putting the projects here.
https://summerofcode.withgoogle.com/

Change-Id: I30df1cce597f909fc5c6834570fb3fc7b5b0582b

tvoli/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player