Pipeline assembly input

[ericenns]

Description of changes

Adds a new input type genomeAssemblies for pipelines which allows running pipelines on Samples assembly files.

Example plugin that uses this new input type can be found here: https://github.com/ericenns/irida-plugin-assembly-input-example

Related issue

Link to the GitHub issue this pull request addresses using the #issuenum format. If it completes an issue, use Fixes #issuenum to automatically close the issue.

Checklist

Things for the developer to confirm they've done before the PR should be accepted:

• [ ] CHANGELOG.md (and UPGRADING.md if necessary) updated with information for new change.
• [ ] Tests added (or description of how to test) for any new features.
• [ ] User documentation updated for UI or technical changes.