view-user --parsable: improve output formatting

[cmoussa1]

Problem

Since the formatting of the columns in the output of view-user --parsable is dependent on the length of the longest column name, the width of every column is forced to match, which can result in some ugly screen wrapping even in a relatively small font.

$ flux account view-user moussa1 --parsable
creation_time   mod_time        active          username        userid          bank            default_bank    shares          job_usage       fairshare       max_running_jobsmax_active_jobs max_nodes       queues          projects        default_project 
1661527404      1661527404      1               moussa1         58985           lc              lc              1               0.0             0.457547        100             1000            2147483647                      *               *   

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This PR improves the formatting of view-user --parsable by making the width of each column dynamic based on the length of each column name instead of based on the length of the longest column name. Below is an example:

$ flux account view-user user1 --parsable
creation_time | mod_time   | active | username | userid | bank | default_bank | shares | job_usage | fairshare | max_running_jobs | max_active_jobs | max_nodes  | queues | projects | default_project
--------------+------------+--------+----------+--------+------+--------------+--------+-----------+-----------+------------------+-----------------+------------+--------+----------+----------------
1729113599    | 1729113599 | 1      | user1    | 65534  | A    | A            | 1      | 0.0       | 0.5       | 5                | 7               | 2147483647 |        | *        | *   

[wihobbs]

Some longer term things you could consider doing:

• take a format string, similar to the flux jobs -o option, so that you only print what the user wants
• bounding the width of the table to the width of a user's terminal (I almost asked you to do this here but I think it's tricky with the amount of data in the table)

[cmoussa1]

Thanks @wihobbs! That's a good suggestion. I'll open an "idea" issue thread that might look into supporting just taking a format string (for all of the data from the DB, not just users). Setting MWP here!