change(ui): Enable the progress bar feature by default, but only show progress bars when the config is enabled

[teor2345]

TODO

After this PR merges, add:

• A changelog feature entry asking for user testing
• A post on the forums encouraging users to test it after it is released, and mentioning the known issue with estimates
• A mention in the Arborist call

Motivation

Currently the progress-bars feature turns on progress bars and file logging when it is enabled.

To make it easier for users to test progress bars, we can make the progress bars configurable with zebrad.toml. This allows us to compile the progress-bar feature by default, but not activate it for every user by default.

(Activating progress bars by default could be a breaking change for some users that expect Zebra to write logs to standard output.)

Close #7363
Close #7364

Complex Code or Requirements

When the progress bar feature is activated, the log file also needs to be activated (unless the user has specifically turned it off).

I added a summary and detailed config, because we might want to have an "expert" mode. But we need to know what users want first!

Solution

• Add a config for progress bars, which is only used when the progress-bars feature is enabled
  • If they are not enabled, log a message telling users how to enable them in the config
  • Document how to enable them in the README
• Enable the progress-bars feature by default in Zebra builds

Testing

• Add a config with progress bars enabled to the config tests
• Make the config tests handle log files correctly
• Check the config path in the config tests

Review

This is a low priority feature, it doesn't need to go in the 1.3.0 release.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

Follow Up Work

Work out which progress bars users want.

[teor2345]

TODO

After this PR merges, add:

• A changelog feature entry asking for user testing
• A post on the forums encouraging users to test it after it is released, and mentioning the known issue with estimates
• A mention in the Arborist call

I have done the first task in PR #7610, I'll put the rest in the appropriate Slack channels.