Re-order bulk metadata to match order for overall sample metadata

[allyhawkins]

In reviewing the sample metadata, we noticed that the bulk metadata and sample metadata is not in the same order. We have some overlapping columns that are present in both, but in a different order. Although this isn't entirely necessary, it might be a good idea to adjust the order to match what's in AlexsLemonade/scpca-portal#699 (comment).

This should be pretty straight forward with some minor edits to generate_bulk_metadata.R to make sure the output TSV has columns in the correct order.

This should be:

project_id
sample_id
library_id 
seq_unit
technology
total_reads
mapped_reads
genome_assembly
mapping_index
salmon_version
total_reads
date_processed
workflow
workflow_version
workflow_commit

[allyhawkins]

Closed by #767