Allow importing individual planes of NV12/P010/P016 D3D textures with
supported SRV/RTV formats.  Restrict these to GL_TEXTURE_EXTERNAL_OES to
limit to using as shader inputs or render targets and prevent
unsupported operations like ReadPixels.

Test: D3DTextureYUVTest*
Bug: angleproject:5538, chromium:1116101
Change-Id: If5bf54f4f75bb2c703890ce3f5fbd67e4461c98f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2338827
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>