Clear name for pack/pack_file/count_xxx

[unkcpz]

    // XXX: combine with get_n_objs and return dicts
    fn get_total_size(&self) -> PyResult<u64> {
        let info = rsdos::cli::stat(&self.inner)?;
        Ok(info.size.loose)
    }

    // FIXME: rename count_loose
    fn get_n_objs(&self) -> PyResult<u64> {
        let info = rsdos::cli::stat(&self.inner)?;
        Ok(info.count.loose)
    }

    fn get_count_pack(&self) -> PyResult<u64> {
        let info = rsdos::cli::stat(&self.inner)?;
        Ok(info.count.packs)
    }

    fn get_count_pack_file(&self) -> PyResult<u64> {
        let info = rsdos::cli::stat(&self.inner)?;
        Ok(info.count.packs_file)
    }

prefix get_ is confuse and not necessary.

    Ok(ContainerInfo {
        location: cnt.path.display().to_string(),
        id: config.container_id.to_string(),
        compression_algorithm: config.compression_algorithm,
        count: CountInfo {
            // number of loose objs
            loose: loose_files_count,
            // number of pack objs
            // FIXME: rename -> pack
            packs: packs_count,
            // number of pack files
            packs_file: packs_file_count,
        },
        size: SizeInfo {
            // total size of all loose objs
            loose: loose_files_size,
            // total size of all pack objs
            packs: packs_size,
            // total size of all pack files
            packs_file: packs_file_size,
            // size of pack index db file
            packs_db: packs_db_size,
        },
    })

prefer pack_file over packs_file?
prefer count.pack_obj over count.packs?