Use params for containers in process definitions

[kelly-sovacool]

Changes

Parallels https://github.com/CCBR/CCBR_NextflowTemplate/pull/15

Issues

Towards https://github.com/CCBR/CCBR_NextflowTemplate/issues/13

PR Checklist

(~Strikethrough~ any points that are not applicable.)

• [x] This comment contains a description of changes with justifications, with any relevant issues linked.
• ~[ ] Write unit tests for any new features, bug fixes, or other code changes.~ testing framework not yet implemented
• ~[ ] Update docs if there are any API changes.~ on backburner until before public release
• ~[ ] If a new nextflow process is implemented:~
• ~[ ] Update CHANGELOG.md with a one-line description of these changes and reference the PR number. Guidelines: https://keepachangelog.com/en/1.1.0/~