`SamplesLoader`

[hepcat72]

Summary Change Description

Added SamplesLoader.

• Fixed doc strings in the animals loader.
• Cleaned up the animals loader imports.
• Removed a reference to the infusates header from the TableLoader.
• Added a columns argument to TableLoader.handle_load_db_errors.
• Fixed the doc string for TableLoader.handle_load_db_errors (it was stale).

Affected Issues/Pull Requests

• Partially addresses #828
• Merges into PR #1001
• Next PR: #1005

Review Notes

See comments in-line.

Checklist

This pull request will be merged once the following requirements are met. The author and/or reviewers should uncheck any unmet requirements:

• Review requirements
  • Minimum approvals: 1
  • No changes requested
  • All blocking issues resolved by reviewers
  • Specific reviewers: @add_username_here
  • Review period: 2 days
• Associated issue/pull request requirements:
  • [x] All requirements in affected issues marked "resolved" are satisfied
  • [x] All required pull requests are merged (or none)
• Basic requirements
  • [x] All linters pass
  • [x] All tests pass
  • [x] All conflicts resolved
• Overhead requirements
  • [x] New/changed method tests implemented/updated (or no change)
  • [ ] Updated Unreleased section of changelog.md (or no change)
  • [x] Migrations created & committed (or no change)