Revert of L16 implementation of the Audio{En,De}coderFactoryTemplate APIs (patchset #5 id:80001 of https://codereview.webrtc.org/2995523002/ )

Reason for revert:
Breaks compilation in google3.

Original issue's description:
> L16 implementation of the Audio{En,De}coderFactoryTemplate APIs
>
> BUG=webrtc:7836, webrtc:7842
>
> Review-Url: https://codereview.webrtc.org/2995523002
> Cr-Commit-Position: refs/heads/master@{#19354}
> Committed: https://chromium.googlesource.com/external/webrtc/+/edff94df62d5cc0563430ed8d5e2ba8c9f88f7dd

TBR=ossu@webrtc.org,kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7836, webrtc:7842

Review-Url: https://codereview.webrtc.org/2996993002
Cr-Original-Commit-Position: refs/heads/master@{#19356}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: ac31526bb5416af4c100787d3826fa582cf21726
11 files changed