docs: update parsing of system definitions for table

[slabasan]

Description

• Update parsing of system definitions for table in docs, move existing table to a legacy catalog of systems
• No dependencies
• Part of Docs: new csv generation for system and benchmark lists #377
• Complete the checklist for a relevant section(s) below
• Delete sections below that are not relevant to this PR
• Update to current develop: all_system_definitions was renamed to all_hardware_descriptions, all system_definition.yaml were renamed to hardware_description.yaml

Open questions:

• Caliper is listed under experiments, but isn't considered a benchmark, should it be appearing in the benchpark list benchmarks command? Move caliper from experiment to lib #577 fixed this.
• Systems table is creating additional columns that I think were meant to be rows. See systems-tested.csc-lumi and systems-tested.llnl-elcapitan columns in screenshot below.

Alternative table (previously, interconnect.name, integrator.vendor):

Adding/modifying core functionality, CI, or documentation:

• Update docs
• Update .github/workflows and .gitlab/ci unit tests (if needed)