Allow scale down at 0% consumed count

[sebdah]

Dynamic DynamoDB is only scaling down when consumed capacity > 0%. That has been implemented as a security enhancement, but in some cases (where the table really has low traffic) it makes sense to scale down at 0%.

Create an option to make 0% down scaling possible.

[sebdah]

The limitation here is that this is only configurable from the configuration file:

allow-scaling-down-reads-on-0-percent: true
allow-scaling-down-writes-on-0-percent: true