compute ddl script

[afleisc]

closes #459

It can be more cost efficient to use either the on-demand or the reservation compute billing model depending on query patterns. This script aims to identify projects that obviously save cost by switching billing models and to provide template DDL to adjust accordingly.

The logic is essentially:

1.) on-demand -> reservations

Compare the on-demand cost to the worst case cost in reservations (all autoscaling). If autoscaling is less expensive, move to reservations.

2.) reservations -> on-demand

Compare the best case scenario for reservations (all baseline) to on-demand cost. If on-demand is less expensive, move to on-demand.