Move webrtc/{tools => rtc_tools}

webrtc/tools/testing/README.md

-This directory contains prebuilt tools used during end-to-end tests.
-They will be downloaded by their SHA1 hash, and are not meant to be checked in.
-
-Updating prebuilt_apprtc.zip:
-
-- Follow AppRTC instructions:
-    - `git clone https://github.com/webrtc/apprtc`
-    - Install NodeJS:
-        - Download <https://nodejs.org/> and extract it
-        - `export PATH="$(pwd)/node-v6.10.3-linux-x64/bin:$PATH"`
-    - `cd apprtc`
-    - `npm install`
-    - `export PATH="$(pwd)/node_modules/.bin:$PATH"`
-    - `pip install --user --upgrade pip setuptools` - needed only on old systems
-    - `grunt`
-- Vendor collider's dependencies:
-    - `ln -s "$(pwd)/src/collider" src/src`
-    - `GOPATH="$(pwd)/src" go get -d collidermain`
-    - `rm src/src`
-- Remove unneeded files:
-    - `rm -rf .git node_modules browsers`
-- `zip -r prebuilt_apprtc.zip apprtc/`
-- `mv prebuilt_apprtc.zip webrtc/src/webrtc/tools/testing/prebuilt_apprtc.zip`
-
-Updating golang/*:
-
-- Go to <https://golang.org/dl/>
-- Download these files:
-    - go*.linux-amd64.tar.gz -> golang/linux/go.tar.gz
-    - go*.darwin-amd64.tar.gz -> golang/mac/go.tar.gz
-    - go*.windows-amd64.zip -> golang/windows/go.zip
-
-After updating the archives:
-
-- `cd webrtc/src/webrtc/tools/testing`
-- For each updated archive:
-    - `upload_to_google_storage.py file.zip --bucket=chromium-webrtc-resources`
-- `git commit -a && git cl upload`