Benchpark info command, new experiment and system directives

[pearce8]

New system.py directives:

name = "lanl-venado"
system_site = "lanl"
system_name = "venado"
hardware = system_hardware_key (from all_system_definitions/system_hardware_key/system_definition.yaml)
maintainer("...")

New experiment.py directives:

url = ...
name = "amg2023"
spack_name = "amg2023"
ramble_name = "amg"
maintainer("...")

Parent classes (CudaExperiment, etc.) directives:

programming_model("cuda")
scaling("strong") 

Benchpark info command needs the following subcommands:

• benchpark info system
• Benchpark info system variants
• benchpark info system hardware
• benchpark info system maintainer
• bechpark info experiment_name
• benchpark info --spack experiment_name
• benchpark info --ramble experiment_name
• benchpark info maintainer
• list from benchpark python script to grab programming models #486