adding new job "attribute" is painful

[grondo]

Currently, in order to add a new job "attribute" to Flux you have to update at least 5 locations:

• const char *attrs[] list of attributes in job-list list_attrs_cb()
• const char *list_attrs string in flux-job.c for cmd_list()
• header format dictionary in flux/job/info.py in the Python bindings
• VALID_ATTRS constant list of valid attributes in flux/job/list.pyin the Python bindings
• The format to attrs mapping in flux-jobs.py

It would be nice if this was a little easier, though I haven't thought of exactly how to do that yet.

[chu11]

#4313 may be able to solve a few of these, which helps

[chu11]

after merge of #4324 this list is shorter / modified

• const char *attrs[] list of attributes in job-list job-list.c
• header format dictionary in flux/job/info.py in the Python bindings
• the expected list-attrs list in t/python/t0010-job.py
• The format to attrs mapping in flux-jobs.py