backup: use multipartUpload to transfer large backup files

[zhijian-pro]

close #5468

[codecov]

Codecov Report

Attention: Patch coverage is 41.93548% with 18 lines in your changes missing coverage. Please review.

Project coverage is 32.97%. Comparing base (5714660) to head (767debe).
Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/vfs/backup.go	57.14%	6 Missing and 3 partials ⚠️
pkg/sync/sync.go	16.66%	5 Missing ⚠️
pkg/meta/sql.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5564       +/-   ##
===========================================
- Coverage   50.57%   32.97%   -17.61%     
===========================================
  Files         166      131       -35     
  Lines       48152    38843     -9309     
===========================================
- Hits        24353    12807    -11546     
- Misses      21076    24769     +3693     
+ Partials     2723     1267     -1456     

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