Add Specific Loader for File Upload Progress Tracking

[Dhenyson]

Is your feature request related to a problem? Please describe

I have been using Portainer for some time, and in some projects, due to internal reasons, we need to manually upload images.tar. We use the image/import/upload feature, and it works well. However, there is an issue that hinders tracking the upload process: the default loader in Portainer, which uses the nprogress library. Currently, the loader in Portainer operates globally and is rendered by various side effects, causing several bugs in its loading process. Regarding the upload itself, the loader never tracks the correct process. Either it changes the progress percentage due to side effects of other actions or it shows 100% completion while the upload still takes a significant amount of time to finish, making real tracking impossible.

Describe the solution you'd like

(Right after this issue, I will be submitting a feature. You can use the solution I provided, but if it's not possible, please let me know why. Thank you.)
I tried to directly correct these side effects in the nprogress percentage, but it is challenging to manage a loader used for multiple processes simultaneously. My solution was to create a loader that specifically checks the file upload progress and displays the percentage more clearly. It is a simple and lightweight code that does not affect the security or stability of Portainer. This feature would be very helpful if implemented.

Describe alternatives you've considered

I waited for hours for a failed upload to complete because the current loader kept showing "loading". This new loader would resolve such issues by providing accurate tracking of the upload progress.

Additional context

No response