refresh some "using python at nersc" content
This MR has a few changes to:
- refresh the "Using Python at NERSC" page.
- replace
lazy-*
env references tonersc-*
env names which are used by the new python modules.
Submitters and reviewers please make sure
-
internal links are relative and to the .md file -
avoid links named "here" -
alt-text for images is descriptive -
doesn't duplicate existing content -
spell check -
renders correctly -
does not include any identifiable information (real usernames, project names, etc)