fix: gzipped files on METABINNER_BINS to prevent race condition

[dialvarezs]

When running MetaBinner on our HPC (storage mounted via NFS), I got the following error:

find: ./bins/.nfs000000100122bb1600001c93: No such file or directory

This happens because when find starts, the file is still visible in the NFS filesystem, but by the time the mv command runs, the file has already been unlinked, throwing an error.
This chamge makes the script generating the bin files gzipped, so the post-execution of gzip and mv is no longer required.

This also changes the boundary of too short bins (< to <=) to align with what the tool does.

PR checklist

• This comment contains a description of changes (with reason).
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