feature request: set assignment submission status via .tsv upload

[lkuper]

The ability to upload assignment scores via a .tsv is great. Along those lines, I want to be able to set the status of an assignment submission (e.g., "late", "missing", "excused").

[eriq-augustine]

Looks like this should be possible:
https://canvas.instructure.com/doc/api/submissions.html#method.submissions_api.update

There are two things to think about:

First.
The API Show two fields that handle what is shown in the Web GUI:
"submission[excuse]" and "submission[late_policy_status]".
This seems like an inaccuracy or error in the documentation (which we have seen several times before).
We will have to examine the HTTP requests made by the Web GUI to figure out how to properly handle the different fields.

Second.
How to denote that a column in the TSV represents this field.
It this was just only going to be one more field, then it would not be an issue.
But, this sounds like it will be the first of more optional fields that will get added.
So, we will need to figure out our convention for optional fields like this.
Maybe a known column name, or command-line option that specifies the column index.

[MAVRICK-1]

@lkuper can I work on this?

[eriq-augustine]

@MAVRICK-1 sure.

Some logistical things to note:

• We don't really reserve issues for new contributors (since there is a lot of variability there), so it's possible for someone else to attempt this issue as well.
• A PR is a much stronger way to "stake a claim" (but even then it is not 100% for new contributors).
• Someone who reports an issue is not always the one who has the authority to assign it. (Anyone can create issues in our repo.)