[FEATURE] Support more than 50 compute resources and queues

[cartalla]

Is your feature request related to a problem? Please describe.
Currently ParallelCluster only supports 50 compute resources and 50 queues.
With memory based scheduling enabled you can only have 1 compute resource per queue and this effectively limits the number of instance types that can be supported.
If you need to configure both spot and on-demand instances then the number of instance types is halved.

The number of configurable instance types is actually higher than 50 since you can have multiple instance types in a compute
resource if they have the same number of cores and same amount of memory.

Describe the solution you'd like
I'd like the limit removed completely.

If it must remain, then it needs to be closer to 500 than 50.