GCP: long project names may cause issues with subnet naming

[nullfunc]

I received this error when deploying sample sample-django-channels-redis-postgres :

error: could not make instance of 'gcp:compute/subnetwork:Subnetwork': name 'sample-django-channels-redis-postgres-template-shared-subnet-' plus 7 random chars is longer than maximum length 63

Any long project name would cause this. we should be able to validate for users before deployment actually occurs.