Prettify and improve download bars during model pulls

[swarajpande5]

This PR prettifies and improves the download bars during model pulls.
Thanks to @ericcurtin for providing the code references from https://github.com/ericcurtin/lm-pull/blob/main/lm-pull.py.

Example run:

(venv) spande-mac:ramalama (prettify-bar) $ ./bin/ramalama pull ollama://tinyllama
  9% |████████                                                                                   |   55.64 MB/ 608.16 MB   3.66 MB/s    2m 30s

Summary by Sourcery

Enhancements:

• Replace tqdm with a custom progress bar implementation for model downloads.

[ericcurtin]

Merging, it would be nice is we could put File and HttpClient in their own files in a follow on PR.

[ericcurtin]

We should also remove every reference to tqdm in a follow on PR.

One of the reasons for writing the progress bar from scratch is to eliminate tqdm as a dependency from the project.

[swarajpande5]

@ericcurtin Thanks for merging.
I'll go ahead and create 2 PRs, one for putting File and HttpClient in their own seperate files;
and other one for removing every reference of tqdm.