Add admin buttons to delete and resubmit samples

[lkeegan]

• add DELETE admin/samples/<sample_id> API endpoint
  • deletes the sample and all associated input files and results
• add delete button to admin interface with modal confirmation dialog
  • resolves #39
• add POST admin/resubmit-sample/<sample_id> API endpoint
  • deletes any existing results for the sample, then sets its status to QUEUED
• add resubmit button to admin interface with modal confirmation dialog
  • resolves #40

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 84.84848% with 5 lines in your changes missing coverage. Please review.

Project coverage is 78.82%. Comparing base (4fb00da) to head (d8b9477).

Files with missing lines	Patch %	Lines
backend/src/predicTCR_server/app.py	82.75%	5 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #45 +/- ## ========================================== + Coverage 78.18% 78.82% +0.63% ========================================== Files 8 8 Lines 651 680 +29 ========================================== + Hits 509 536 +27 - Misses 142 144 +2 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.