feat: add log message color configuration

[Wafffle77]

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Description

Adds a --log-color option for controlling colored log output. In addition to "on" and "off", "auto" (the default) will detect whether or not stderr is a terminal and act accordingly.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

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[synackd]

I tested this and it works well.

However, there is a missing piece that is required for config merging to work correctly. For instance, if I:

# Set value in user config
ochami config set log.color on

I can see it get changed in the user config:

$ ochami config show log.color --user
on

But the merged config uses the default value:

$ ./ochami config show log.color
auto

To fix this, we'll have to add a case for this config value in the custom config unmarshaller. There is already code there for timeout (case statement, default value setting) that can serve as a reference.

[synackd]

I adjusted the title of this PR to follow Conventional Commit format for the future squash merge.