feat: Allow to install backend from file with .zip instead of .tar.gz

[LazyYuuki]

Problem Statement

Currently, in 0.6.10, we can only install a llama.cpp backend using .tar.gz and not .zip which is how llama.cpp built is distributed.

Feature Idea

Allow user to just install directly from .zip file instead

[github-roushan]

@LazyYuuki
can you look at this

[github-roushan]

I was able to install llama-b6527-bin-ubuntu-x64.zip from upload file and other backends from the dropdown

[LazyYuuki]

Hi @github-roushan thanks for the PR, cc @qnixsynapse here to help take a look if this is the intended implementation