Add endpoint to archive a transformation request

[AndrewEckart]

• New endpoint at servicex/transformation/<uiid>/archive
• New TransformRequest.archived boolean model attribute
• Database migration script
• Minio cleanup logic using Suchandra's new library
• Unit tests

[codecov]

Codecov Report

Merging #152 (7dd3c7c) into develop (123265e) will decrease coverage by 0.73%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##           develop     #152      +/-   ##
===========================================
- Coverage    90.89%   90.16%   -0.74%     
===========================================
  Files           52       53       +1     
  Lines         1483     1505      +22     
  Branches       126      128       +2     
===========================================
+ Hits          1348     1357       +9     
- Misses         121      134      +13     
  Partials        14       14              

Impacted Files	Coverage Δ
servicex/resources/transformation/archive.py	31.57% <31.57%> (ø)
servicex/models.py	82.35% <100.00%> (+0.08%)	⬆️
servicex/routes.py	100.00% <100.00%> (ø)

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