feat(frontend): uploading multiple files

[amanape]

Summary

Extend the frontend file explorer to support uploading multiple files (partial #1379)

Todo

• User can upload directories via input
  • Because of the nature of the input element with file-handling, we have to create a separate input for uploading files, and another for folders. For this, I implemented a dropdown when clicking the upload icon, that prompts the user to select the type of upload.
• User can upload files/directory via drag-and-drop
• User can download selected files/directories (ZIP?)
  • After facing some issue and some more thought, it is probably best and less risky to move downloading to another issue/PR

Notes

Extend to support uploading directories directly is not straightforward. Other than certain browser incompatibility with the regular input for uploading, it becomes worse when trying to support it for drag-and-drop.

For now, this PR only focuses on single and multiple file uploads. Directories should be a separate PR.

Any suggestions or additional requirements are welcomed

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes are missing coverage. Please review.

❗ No coverage uploaded for pull request base (main@00c0eda). Click here to learn what that means.

Files	Patch %	Lines
opendevin/server/listen.py	0.00%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1718   +/-   ##
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  Coverage        ?   64.29%           
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  Files           ?       99           
  Lines           ?     4055           
  Branches        ?        0           
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  Hits            ?     2607           
  Misses          ?     1448           
  Partials        ?        0           

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[xingyaoww]

LGTM & tested! Both dragging and multiple file upload works!