Add support for cancel backups

[dirkkul]

List backups has been moved back, but I'll leave the code that has already been written in there

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 44.18605% with 24 lines in your changes missing coverage. Please review.

Project coverage is 94.27%. Comparing base (624e2e2) to head (26da9be).
Report is 66 commits behind head on main.

Files with missing lines	Patch %	Lines
weaviate/backup/backup.py	37.03%	17 Missing ⚠️
integration_v3/test_backup_v4.py	41.66%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1264      +/-   ##
==========================================
- Coverage   94.38%   94.27%   -0.11%     
==========================================
  Files         220      220              
  Lines       20953    20993      +40     
==========================================
+ Hits        19776    19792      +16     
- Misses       1177     1201      +24     

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