Benchpark version clones spack

[pearce8]

Describe the bug
benchpark version clones spack

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://software.llnl.gov/benchpark/getting-started.html'
2. Follow the directions we give users
3. Notice the spack cloning when you type benchpark version

Expected behavior
Are we subsequently using the cloned spack? If not, should we be having instructions here - or move the version check to after a workspace is created?

Supercomputer (please complete the following information):

• system: any

[michaelmckinsey1]

In main.py, import benchpark.cmd.audit calls bootstrapper.bootstrap(), which is what installs ramble and spack if they do not already exist in the path (i.e. will happen for fresh install).

One way I can think of to address this is to check before the import and exit if using benchpark -V or benchpark --version, like here #595