Turning off Builder builds

Some specific scenarios (for example, base plan uploads) may require build-on-upload functionality to be turned off.

Currently, we can only do that by turning off all Builder builds.

In order to do that, log onto the datastore node, and modify the `builder-api.toml' file.

Under the depot section, set the builds_enabled flag to false. Eg:

[depot]
builds_enabled = false

Once that is done, run the ./apply_config.sh script.

Don't forget to turn the builds back on by setting the flag back to true and re-applying the configs when done.