util.human.io: table: Return determined width as a second result This allows callers to adjust other things based on the width of the rows (such as header lines).

util.human.io: Prefer using the $COLUMNS environment variable if set (by readline) Feels like it should be faster.

util.prosodyctl.shell: Use new term_width() for width Kicks in if/when readline hasn't set $COLUMNS, e.g. when using the `prosodyctl shell command like this` form.

util.human.io: table: use term_width() to discover terminal width

util.human.io: Add term_width() method to discover the terminal width This is not standard POSIX, but apparently very widely supported. For reference: https://www.austingroupbugs.net/view.php?id=1053

mod_admin_shell: Make IP column thinner if IPv6 is disabled IPv6 addresses can be pretty long, so if they can be more compact, that's nice. But nobody would disable IPv6, would they?

mod_admin_shell: Make default column width 1 part These gets used for usernames, resources and other random session fields that don't have a column definition in `available_columns`

mod_admin_shell: Fix attempt to compare number with string Missed the # in 93c1590b5951

util.human.io: Pass the whole column definition to mapper function I forget why I wanted this, but it may allow doing things like pull settings from the column, especially when the mapper function is reused among many columns.

util.human.io: Allow defining per column ellipsis function As an alternative to doing it in the mapper function. Could be useful in cases where one may want to put the ellipsis in the middle or beginning instead of the start.