implement workload deletion

[alexandrebrg]

What needs to be done ?

• Controller handling of a workload deletion
  • Entry must be deleted from database
  • Related instances must be deleted from database
• Ensure riklet function deletion handling is complete
  • Instance deletion should delete file related to the instance
  • To be discussed: when and how to handle workload cache deletion
• Full deletion handling of instances of a workload in scheduler

Why it needs to be done ?

• Dependent project Morty needs to be able to delete workloads

[MaloPolese]

@alexandrebrg everything is already done in controller right ?