Hardcoded organization name prevents github actions from running in a forked repository

[asjohnston-asf]

A couple places in the docker build/push/pull/run scripts assume the github organization is nasa in the GHCR url. That leads to "permission denied" errors when I try to build or run the tests from my asjohnston-asf fork.

1. https://github.com/nasa/harmony-regression-tests/blob/main/.github/workflows/notebook-test-suite.yml#L135
2. https://github.com/nasa/harmony-regression-tests/blob/main/script/image_name.sh#L18

The first can be easily generalized by using ${{github.repository_owner}}, but I don't see a trivial fix for the second.

I was able to work around this by editing the owner in a separate branch and running the test action from that branch via workflow dispatch (after building the container from my feature branch).