improve prepare_images and increase duration

[pengshanyu]

1. When each test case is executed, if directory /var/qm/lib/containers/registry exists, delete it first, then create the directory and copy the ffi-tools container image to it.
2. Pulling ffi-tools image often times out, so extend the duration.

Resolve #506

[Yarboa]

I assume we should consider shrinking ffi-tools
I mean move more rpms into the condition, @pengshanyu, WDYT?

[dougsland]

@nsednev maybe you need this patch?

[pengshanyu]

I assume we should consider shrinking ffi-tools I mean move more rpms into the condition, @pengshanyu, WDYT?

Yes, let's try to shrink ffi-tools. I am not familiar with some packages, could you give me some guidance?

[dougsland]

safe to merge, helping reduce the size. CI/CD might be get better with the patch btw. @Yarboa will provide in an Github Issue maybe? ideas for improvement for reducing the size?