All `Python` modules now export `PIP_REQUIRE_VIRTUALENV=true`.
This causes an error when users try to use `pip install` without an
active virtualenv.
This also avoids admins accidentally installing/changing Python packages
in the global module.

update pika page: add 2 metrics; add download jobdata screenshot, explanation and example; remove haswell warning

Update python_virtual_environments.md: insert missing line. When executing this example, there is a conda init error raised if this line was not executed previously.

- Currently no such partition available on any cluster

- Fix some line breaking
- Fix some long slurm options

Closes #573