Remove hardcoded inputs and outputs in collect_accessions.py

[mbonsma]

collect_accessions.py (PR #243) has file names hardcoded in the input and output. It should be modified to:

• accept the input and output filenames as command line arguments, and
• have a docstring that explains what the arguments are and what the script does.

See crispr_finder.py for an example of a docstring (top rows in triple quotes) and accepting arguments.

[ghost]

Hi - can I work on this bug as part of Hacktoberfest?!

[mbonsma]

@thegreyelephant sure, please do!

[thisisjaid]

Sorry I had kind of already addressed this as part of the Pandas rewrite PR :/

[ghost]

@thisisjaid Oh - OK. No worries, I'll look for another beginner bug!

[QuLogic]

@mbonsma So close this?