[FEA] Add user qualification tool options for specifying pricing discounts for CPU or GPU cluster, or both

[cindyyuanjiang]

Fixes #476

We add three new user qualification tool options (for both spark_rapids_user_tools and ascli CLI)

• --cpu_discount: the specified percentage discount for the CPU cluster cost to be reduced by (e.g. 30 for 30% discount)
• --gpu_discount: the specified percentage discount for the GPU cluster cost to be reduced by
• --global_discount: the specified percentage discount for both cluster costs to be reduced by. Note that if --global_discount is specified, neither --cpu_discount nor --gpu_discount should be specified, otherwise the tool will raise an exception

Follow up work:
We need to update documentation, issue tracked here: #584

[cindyyuanjiang]

We tested the PR change with the following script:

export EVENT_LOGS=... # a local event log file
export PLATFORM=... # the csp platform we want to test
export CPU_CLUSTER_PROPS=... # the cpu cluster properties file for the relative platform

########################################
# running each of the CSP platforms
########################################

# run the following commands and confirm the discount calculations are correct
spark_rapids_user_tools $PLATFORM qualification \
  --eventlogs $EVENT_LOGS \
  --cpu_cluster $CPU_CLUSTER_PROPS

spark_rapids_user_tools $PLATFORM qualification \
  --eventlogs $EVENT_LOGS \
  --cpu_cluster $CPU_CLUSTER_PROPS \
  --cpu_discount 30

spark_rapids_user_tools $PLATFORM qualification \
  --eventlogs $EVENT_LOGS \
  --cpu_cluster $CPU_CLUSTER_PROPS \
  --cpu_discount 30 \
  --gpu_discount 30

ascli qualification \
  --platform $PLATFORM \
  --eventlogs $EVENT_LOGS \
  --cluster $CPU_CLUSTER_PROPS

ascli qualification \
  --platform $PLATFORM \
  --eventlogs $EVENT_LOGS \
  --cluster $CPU_CLUSTER_PROPS \
  --gpu_discount 30

ascli qualification \
  --platform $PLATFORM \
  --eventlogs $EVENT_LOGS \
  --cluster $CPU_CLUSTER_PROPS \
  --cpu_discount 30 \
  --gpu_discount 30

########################################
# failures
########################################

# running a command when global_discount is specified with cpu_discount, gpu_discount, and both

# running a command with non-integer input for cpu_discount, gpu_discount, and global_discount

# running a command with int input for cpu_discount, gpu_discount, and global_discount that is out of range [0, 100]

[nartal1]

Thanks @cindyyuanjiang! Just a nit to remove redundancy and better readability. Otherwise, LGTM.

[parthosa]

Thanks @cindyyuanjiang. Added a few minor comments.