docs(storage): add file upload and download examples

[suzmue]

Fixes #3071 and fixes #3099

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.52%. Comparing base (3d8435f) to head (5746a58).
⚠️ Report is 43 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3140      +/-   ##
==========================================
+ Coverage   96.50%   96.52%   +0.02%     
==========================================
  Files         108      108              
  Lines        4407     4407              
==========================================
+ Hits         4253     4254       +1     
+ Misses        154      153       -1     

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