`limactl list --all-fields` only works when output is to a terminal

[jandubois]

There is no way to specify the desired width if output is to a stream or pipe:

❯ l ls --all-fields
NAME    STATUS     SSH            VMTYPE    ARCH       CPUS    MEMORY    DISK    DIR
bar     Stopped    127.0.0.1:0    vz        aarch64    4       4GiB      2MiB    ~/.lima-empty/bar
baz     Stopped    127.0.0.1:0    vz        aarch64    4       4GiB      3MiB    ~/.lima-empty/baz
foo     Stopped    127.0.0.1:0    vz        aarch64    -1      4GiB      1MiB    ~/.lima-empty/foo

❯ l ls --all-fields | cat
NAME    STATUS     SSH            CPUS    MEMORY    DISK    DIR
bar     Stopped    127.0.0.1:0    4       4GiB      2MiB    ~/.lima-empty/bar
baz     Stopped    127.0.0.1:0    4       4GiB      3MiB    ~/.lima-empty/baz
foo     Stopped    127.0.0.1:0    -1      4GiB      1MiB    ~/.lima-empty/foo

This also makes it impossible to create integration tests for it.

Suggestion: add --width option to specify the terminal width. Should override even actual width when writing to a terminal.

[jandubois]

This is not super important, and I only noticed this because I was trying to write a test for --all-fields and couldn't.

1. The simplest solution would actually be to treat an unknown width (width == 0 because stdout is not a TTY) as unlimited width, so we would always include the ARCH and DIR columns when writing to a file.

   This would be my preferred choice, and I'm not clear why we treated output to a file as requiring minimal columns.

2. Add a --width option. This seems like feature creep to me, because I don't think normal users would ever use it.

3. Add another environment variable just for testing, e.g. _LIMA_TERMINAL_WIDTH=80 that would allow tests to simulate various terminal widths.

I'm fine implementing any of them; and will pick (1) unless people argue for (2) or (3) (or have a different idea).