Go- and gitless installation of docsy theme

[deining]

Currently, we are in the process of adding the option to use docsy as Hugo module (#871).
Not all all existing installation will immediately switch over to hugo modules, though git submodules are outdated and we want to get rid of them (#870). One concern is that when using hugo modules, go must be installed. While this is true for anyone who wants to do development with modules, go is not strictly necessary when using hugo modules.

This issue wants to elaborate on the go- and gitless approach a bit. In order to make a go- and gitless installation, the following steps are needed:

hugo new site go-and-gitless-site
cd go-and-gitless-site
wget https://github.com/deining/docsy/releases/download/v0.2.0-pre/_vendor.zip
unzip _vendor.zip
rm _vendor.zip
echo 'theme = ["github.com/google/docsy", "github.com/google/docsy/module"]' >> config.toml
hugo serve

The downloaded file vendor.zip contains all needed dependencies (bootstrap, Font-Awesome). The .zip file has 2 MB, unpacked ~5MB.

Just want to illustrate and show new ways of docsy installation. Not sure if this could or should be one official/recommended way of installing docsy.

Thoughts?