add additional config variables to control inversion step resource allocation

[laestrada]

Name and Institution (Required)

Name: Lucas Estrada Institution: Harvard ACMG

Describe the update

Optionally allow user to control the resources allocated to the inversion step separately from the RequestedMemory and RequestedCPUs. If InversionMemory and InversionCPUs are not set, then the default Memory and CPUs will be used.