Add progress bars to skynet directory upload

MERGE REQUEST

Overview

The goal of the merge request is to add progress bars to the output of siac skynet upload that reflect the uploading of files to Skynet. This must be done while preserving the parallel nature of those uploads. There will be a preset limit on the number of concurrent uploads and as soon as one finished another will start, so we will constantly have the max number of concurrent files being processed.

Aside from being uploaded a file also needs to be processed. We need to indicate the progress on that as well. It would be best to have a second stage progress bar for this (either an endless spinner or a full progress bar).

Example for Visual changes (ie Screenshot)

Some options on how the UX might look:
op 1: https://asciinema.org/a/jrIkcuEdxqQGawDweWD6CO3Rw
op 2: https://asciinema.org/a/jFGfPK8x634hJPD65W7PFvOpb
op 3: https://asciinema.org/a/VKz5ul0J70RiNFK4xOULAkFEl

Currently it looks like this:

Issues Closed

N/A

Notes

I looked into several libraries:

• https://github.com/cheggaaa/pb and https://github.com/cheggaaa/pb/v3: very nice bars but only experimental and really rudimentary support for multiple bars.
• https://github.com/sethgrid/multibar: very good multibars but no dynamic adding/removing of bars. Also a little fragile and unreliable - when printing text on the screen it would sometimes print parts of previous buffers.
• https://github.com/vbauerster/mpb: seems to have all the features I need, actively developed.

Check if there's a way to get the progress towards getting 1x redundancy on the skyfile and update the progress bars accordingly.

We also need tests for the siac upload command in order to ensure it works as expected.

Checklist

Review and complete the checklist to ensure that the MR is complete before assigned to an approver.

• All new methods, or updating methods have clear docstrings
• [ ] Testing added or updated for new methods
• [ ] Any new packages are added to Makefile and .gitlab-ci.yml
• [ ] API documentation updated for API updates
• [ ] Module README.md updated for changes to work flow
• [ ] Issue added to Sia-UI repo for new supporting features
• Changelog updated

Closes #3871 (closed)