Readme Cleanup

[cimnine]

Related Issue: n/a

New Behavior

• The README has been updated to reflect the change in the build system and to update other outdated information.
• The Github Action workflows carry specific names. This is to support the next item:
• The shield for the build status is rendered based on the status of the Github Action Workflow called release.

Contrast to Current Behavior

The shield is based on the build status of Docker Hub's build system. We used that system before, but don't use it anymore. The README also contained outdated information.

Discussion: Benefits and Drawbacks

The benefit is that we provide accurate information.

Changes to the Wiki

n/a

Proposed Release Note Entry

n/a

Double Check

• I have read the comments and followed the PR template.
• I have provided and explained my PR according to the information in the comments.
• My PR targets the develop branch.