Required gcloud configuration not created

[sersorrel]

To run an IVM image build, you need a gcloud config called e.g. qmul-testing (or qmul-production), which I set up something like so:

$ gcloud config configurations create qmul-testing
$ # NB: make sure you are *not* in ~/finngen!
$ # otherwise, you will automatically switch back to the `finngen` configuration
$ gcloud config configurations activate qmul-testing
$ gcloud config set account my_admin_account@genesandhealth.qmul.ac.uk
$ gcloud config set project fg-qmul-testing-build
$ gcloud config set compute/region europe-west2
$ gcloud config set compute/zone europe-west2-b

The ansible scripts here don't set that up for you, but they probably should.

The "building software assets" section on confluence also seems out-of-date and should be deleted.