docker ps: always use --quiet, also combined with --format

[thaJeztah]

• follow-up to Fix psFormat's Size handling in config file #3640
• see the discussion on cli/command: ps: only check format-template once photra/cli#1 (comment)
• fixesdocker ps -q does not work if the config file contains a psFormat #4093
• supersedes / closescli: do not apply configfile's psFormat when --quiet is passed #4040

Previously, the formatter would ignore the quiet option if a custom format
was passed; this situation was handled in runPs(), where custom formats
would only be applied if the quiet option was not set, but only if the
format was set in the CLI's config.

This patch updates NewContainerFormat() to do the same, even if a --format
was passed on the command-line.

This is a change in behavior, so may need some discussion; possible alternatives;

• produce an error if both --format and --quiet are passed
• print a warning if both are passed (but use the logic from this patch)

Before this patch:

docker ps --format '{{.Image}}'ubuntu:22.04alpinedocker ps --format '{{.Image}}' --quietubuntu:22.04alpinemkdir -p ~/.docker/echo '{"psFormat": "{{.Image}}" > ~/.docker/config.jsondocker psubuntu:22.04alpinedocker ps --quietubuntu:22.04alpine

With this patch applied:

docker ps --format '{{.Image}}'ubuntu:22.04alpinedocker ps --format '{{.Image}}' --quiet40111f61d5c5482efdf39facmkdir -p ~/.docker/echo '{"psFormat": "{{.Image}}" > ~/.docker/config.jsondocker psubuntu:22.04alpinedocker ps --quiet40111f61d5c5482efdf39fac

docker ps: print warning if both --format and --quiet are set

Of both "--quiet" and "--format" are set, --quiet takes precedence. This
patch adds a warning to inform the user that their custom format is not
used:

docker ps --format='{{.Image}}'
ubuntu:22.04
alpine
docker ps --format='{{.Image}}' --quiet
WARNING: Ignoring custom format, because both --format and --quiet are set.
40111f61d5c5
482efdf39fac

The warning is printed on STDERR, so can be redirected:

docker ps --format='{{.Image}}' --quiet 2> /dev/null
40111f61d5c5
482efdf39fac

The warning is only shown if the format is set using the "--format" option.
No warning is shown if a custom format is set through the CLI configuration
file:

mkdir -p ~/.docker/
echo '{"psFormat": "{{.Image}}"}' > ~/.docker/config.json
docker ps
ubuntu:22.04
alpine
docker ps --quiet
40111f61d5c5
482efdf39fac

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

Merging #3666 (37e02ff) into master (d49b8ff) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@ Coverage Diff @@## master #3666 +/- ##
=======================================
Coverage 59.03% 59.04% =======================================
Files 288 288 Lines 24776 24781 +5 =======================================
+ Hits 14627 14632 +5 
Misses 9265 9265 Partials 884 884 

[thaJeztah]

@vvoland@rumpl@laurazard PTAL (I added the warning we discussed during one of our triage sessions)

[thaJeztah]

Thx! Let me bring this one in 👍