Revert "Move wiki pages to github pages (#18497)"

This reverts commit 40eb803de1.

docs/_doc/Installing-Go.md

@@ -1,40 +0,0 @@
----
-title: Installing Go
----
-### Windows 
-
-Download and run the installer found at http://golang.org/doc/install
-
-### OS X
-
-Download an install the darwin binary from https://golang.org/dl/
-
-You can also install go using the Homebrew package manager.
-
-### Linux
-
-#### Ubuntu
-
-The Ubuntu repositories carry an old version of Go.
-
-Ubuntu users can use the 'gophers' PPA to install an up to date version of Go (version 1.7 or later is preferred).
-See https://launchpad.net/~gophers/+archive/ubuntu/archive for more information.
-Note that this PPA requires adding `/usr/lib/go-1.X/bin` to the executable PATH.
-
-#### Other distros
-
-Download the latest distribution
-
-`curl -O https://storage.googleapis.com/golang/go1.7.3.linux-amd64.tar.gz`
-
-Unpack it to the `/usr/local` (might require sudo)
-
-`tar -C /usr/local -xzf go1.7.3.linux-amd64.tar.gz`
-
-#### Set GOPATH and PATH
-
-For Go to work properly, you need to set the following two environment variables:
-
-- Setup a go folder `mkdir -p ~/go; echo "export GOPATH=$HOME/go" >> ~/.bashrc` 
-- Update your path `echo "export PATH=$PATH:$HOME/go/bin:/usr/local/go/bin" >> ~/.bashrc`
-- Read the environment variables into current session: `source ~/.bashrc`