Feat 50: Dynamically generate job template

[helen-m-lin]

closes #50

• Created JobUploadTemplate class to configure and create job upload template xlsx file
  • Note: there will be a future ticket to convert this class to a pydantic model
• Created /api/job_upload_template endpoint to download template as xlsx file
  • Note: this endpoint generates a new xlsx file stream everytime; there will be a future ticket to add caching.
• Updated "Job Submit Template" links/ tabs in UI
• Added unit tests and new test suite as appropriate

[jtyoung84]

• Note: this endpoint generates a new xlsx file stream everytime; there will be a future ticket to add caching.

I tested it out and it's probably quick enough to not need caching.