[doc] Add suggestions for deploying multiple compilers locally. (#4932)

I attempted to set up a multi-compiler CE instance in an offline
environment. As a result, I added the steps for setting it up to the CE
documentation.

README.md

@@ -89,6 +89,12 @@ If you want to point it at your own GCC or similar binaries, either edit the `et
 else make a new one with the name `LANG.local.properties`, substituting `LANG` as needed. `*.local.properties` files
 have the highest priority when loading properties.
 
+If you want to support multiple compilers and languages like [godbolt.org](https://godbolt.org), you can use the
+`bin/ce_install install compilers` command in the [infra](https://github.com/compiler-explorer/infra) project to install
+all or some of the compilers. Compilers installed in this way can be loaded through the configuration in
+`etc/config/*.amazon.properties`. If you need to deploy in a completely offline environment, you may need to remove some
+parts of the configuration that are pulled from `www.godbolt.ms@443`.
+
 When running in a corporate setting the URL shortening service can be replaced by an internal one if the default storage
 driver isn't appropriate for your environment. To do this, add a new module in `lib/shortener/myservice.js` and set the
 `urlShortenService` variable in configuration. This module should export a single function, see the