Add occ command to set theming values

[juliusknorr]

Fixes#14321 by moving existing logic out of the controller and reusing it in a new occ command.

occ theming:config --help
Description:
Set theming app config values
Usage:
theming:config [options] [--] [<key> [<value>]]
Arguments:
key Key to update the theming app configuration (leave empty to get a list of all configured values)
One of: name, url, imprintUrl, privacyUrl, slogan, color
value Value to set (leave empty to obtain the current value)
Options:
-r, --reset Reset the given config key to default
-h, --help Display this help message
-q, --quiet Do not output any message
-V, --version Display this application version
--ansi Force ANSI output
--no-ansi Disable ANSI output
-n, --no-interaction Do not ask any interactive question
--no-warnings Skip global warnings, show command output only
-v|vv|vvv, --verbose Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug

Example commands

• Change the color: occ theming:config color "#ff0000"
• Change the logo: occ theming:config logo /tmp/foo.png
• Reset the color: occ theming:config color

[juliusknorr]

Guess i was a bit to quick, tests need adjustments as well

[kesselb]

Value to set (leave empty to reset the key to the default value)

Fine by me (because documented) but I would expect that no value prints the current value.

[juliusknorr]

Fine by me (because documented) but I would expect that no value prints the current value.

Now that you mention it, yeah let me add a reset flag.

[juliusknorr]

Ready for review

[rullzer]

/backport to stable20

[blizzz]

/backport to stable19

[juliusknorr]

Already documented at nextcloud/documentation#8078