Defining suites

Previous notes in #64 and #567.

Example: llnl-ci suite (which benchmarks we want to run in CI)

Currently, this looks like:
```
benchpark system init ....
benchpark experiment init exp1 params...
benchpark experiment init exp2 params...
benchpark experiment init exp3 params...
```

How can we make the list of benchmarks (e.g., experiment_list = [amg2023 with params,kripke with params ,rajaperf]) a stored class(?) which will make initialization look like this:
```
benchpark system init ....
benchpark experiment init experiment_list
```