Delete sequence files from file storage when removed from sample

[ksierks]

Description of changes

Added functionality to delete files from file storage when sequence files are removed from a sample.
Note, only files that have no analysis or sequence runs associated with it will be removed from file storage.
For now, the file is remove if it's apart of a concatenated file, as cleaning up nested concatenated files gets complicated.

Testing Instructions

1. Test removing sequence files

• login to IRIDA
• create a sample under a project
• add sequence file(s) to sample
• verify files are on file system
• remove sequence file(s) from sample
• verify files are not file system

2. Test removing sequence files during project synchronization

• login to IRIDA
• create a sample under a project
• add sequence file(s) to sample
• verify files from source project are on file system
• initialize a project synchronization
• verify files from target project are on file system
• remove sequence file(s) from sample within source project
• verify files from source project are on file system
• synchronize the target project
• verify files from target project are on file system

Reminder to test (nested) concatenated sequence files too.

Related issue

#1125

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.

[deepsidhu85]

Looks good other than the one comment below

[deepsidhu85]

Just one comment

[ericenns]

Generally this is looking good, just left some comments on how to improve the code for readability.

[deepsidhu85]

Looks good to me!

[ericenns]

Looks good to me!