Meta-issue: Consolidate MatFlow documentation

[gcapes]

There are already lots of issues on this mamoth theme, so here's a meta-issue to keep track of them

• Move information from this repo to MatFlow docs as appropriate #23
• Environment management: Conda or venv?? non-repo-issues#39
• Confliciting advice about venv usage #32
• CSF setup: Why not module purge? #30
• Don't repeat anything from official MatFlow docs wiki#34
• Add tutorial for running small demo workflow on local machine hpcflow/hpcflow-shared-docs#8
• Delete info which is now in matflow official docs #45