Refactor hbd txfm configurations to be 1D
The hbd transform configurations were originally written for all possible 2d transforms. Now that there are many more possible 2d transforms due to EXT_TX and RECT_TX, it is simpler to write the cfg for the 4 1D transform types and compose them to make all new possible transform types. This will allow for an easier integration of the identity transform for EXT_TX and rectangular transforms for RECT_TX into the current hbd transform codepath and facilitate the removal of obsolete transforms. This has no impact on performance. BUG=aomedia:524 Change-Id: I1e217bcd217fd637b1df94fae62d9c59a0523c1a